X times 1 - Max has a 5 \times 6 card and he enlarged it to be 7.5 \times 9. What was the scale factor? ... First lets forget about the decimal places and multiply 405 x 11. that ...

 
All the constructions that you used to define the isomorphism are natural/functorial: Given a map X →Y, you have a natural map that respect inclusions, which gives a starting point for all the ... Let X =R. The homotopy will be from the identity map to itself, so H (0,x)= H (1,x)= x for all x. For each integer n ≥ 1, during the time period ... . Angler

In order to show that T is a function, you need to prove that for each pair of subsets A and B of X there is one and only one subset U of X\times X such that T(A,B)=U, that is, ((A,B),U) \in T ... Simplify 1/ ( square root of x) 1 √x 1 x. Multiply 1 √x 1 x by √x √x x x. 1 √x ⋅ √x √x 1 x ⋅ x x. Combine and simplify the denominator. Solve your math problems using our free math solver with step-by-step solutions. Our math solver supports basic math, pre-algebra, algebra, trigonometry, calculus and more. Simplify x^ (1/2)*x^ (1/2) x1 2 ⋅ x1 2 x 1 2 ⋅ x 1 2. Multiply x1 2 x 1 2 by x1 2 x 1 2 by adding the exponents. Tap for more steps... x1 x 1. Simplify x1 x 1.Solve your math problems using our free math solver with step-by-step solutions. Our math solver supports basic math, pre-algebra, algebra, trigonometry, calculus and more.Solve your math problems using our free math solver with step-by-step solutions. Our math solver supports basic math, pre-algebra, algebra, trigonometry, calculus and more. 1. negative of (4 squared) is -4² = -(4)² = -(4 × 4) = -16. 2. (negative 4) squared is (-4)² = (-4 × -4) = 16. Use parentheses to clearly indicate which calculation you really want to happen. Squared. A number n squared is written as n² and n² = n × n. If n is an integer then n² is a perfect square.Sep 2, 2012 · The numpy.repeat has been mentioned, and that's clearly the equivalent to what you want. But for completenes' sake, there's also repeat from the itertools standard library. . However, this is intended for iterables in general, so it doesn't allow repetions by index (because iterables in general do not have an index defin Solve your math problems using our free math solver with step-by-step solutions. Our math solver supports basic math, pre-algebra, algebra, trigonometry, calculus and more. We could have factored this numerator as x plus 4 times x plus 1. 4 times 1 is 4. 4 plus 1 is 5, all of that over x plus 4. That cancels out and you're left just with x plus 1. Either way would have worked, but the algebraic long division will always work, even if you can't cancel out factors like that, even if you did have a remainder.The numpy.repeat has been mentioned, and that's clearly the equivalent to what you want. But for completenes' sake, there's also repeat from the itertools standard library. . However, this is intended for iterables in general, so it doesn't allow repetions by index (because iterables in general do not have an index definTo write 1 y 1 y as a fraction with a common denominator, multiply by x x x x. 1 x ⋅ y y + 1 y ⋅ x x 1 x ⋅ y y + 1 y ⋅ x x. Write each expression with a common denominator of xy x y, by multiplying each by an appropriate factor of 1 1. Tap for more steps... y xy + x xy y x y + x x y. Combine the numerators over the common denominator.Free math lessons and math homework help from basic math to algebra, geometry and beyond. Students, teachers, parents, and everyone can find solutions to their math problems instantly.Algebra. Simplify 1/2x^ (-1/2) 1 2 x−1 2 1 2 x - 1 2. Rewrite the expression using the negative exponent rule b−n = 1 bn b - n = 1 b n. 1 2 ⋅ 1 x1 2 1 2 ⋅ 1 x 1 2. Combine. 1⋅1 2x1 2 1 ⋅ 1 2 x 1 2. Multiply 1 1 by 1 1. 1 2x1 2 1 2 x 1 2., the numerator is 3, and the denominator is 8. A more illustrative example could involve a pie with 8 slices. 1 of those 8 slices would constitute the numerator of a fraction, while the total of 8 slices that comprises the whole pie would be the denominator. If a person were to eat 3 slices, the remaining fraction of the pie would therefore be1. negative of (4 squared) is -4² = -(4)² = -(4 × 4) = -16. 2. (negative 4) squared is (-4)² = (-4 × -4) = 16. Use parentheses to clearly indicate which calculation you really want to happen. Squared. A number n squared is written as n² and n² = n × n. If n is an integer then n² is a perfect square.Solve your math problems using our free math solver with step-by-step solutions. Our math solver supports basic math, pre-algebra, algebra, trigonometry, calculus and more. B- 8. Which expression is equivalent to (StartFraction 125 squared Over 125 Superscript four-thirds Baseline EndFraction? D- 25. Which of the following is equivalent to 36 Superscript negative one-half? D- 1/6. Which expression is equivalent to (x Superscript 27 Baseline y) Superscript one-third? B- x^9 (3cubed squareroot y)Associative property of multiplication: Changing the grouping of factors does not change the product. For example, (2 \times 3) \times 4 = 2 \times (3 \times 4) (2×3)×4 = 2×(3×4). Identity property of multiplication: The product of 1 1 and any number is that number. For example, 7 \times 1 = 7 7 ×1 = 7.Free math lessons and math homework help from basic math to algebra, geometry and beyond. Students, teachers, parents, and everyone can find solutions to their math problems instantly. By definition, (x,x)= {{x},{x,x}}. This last set is equal to {{x},{x}} ... Equivalence Relation, and finding the subset that defines the relation. Mostly right, which means wrong. The Transitive proof is correct. The symmetric proof is correct, but cluttered. You just have to say that: as multiplication of reals is commutative, then xy >0 ...Free math problem solver answers your algebra, geometry, trigonometry, calculus, and statistics homework questions with step-by-step explanations, just like a math tutor.First we prove an intermediate result. Subtract 0 × 0 0 × 0 from each side to get 0 = 0 × 0 0 = 0 × 0. Now we are ready for the final kill. = 1 × 1 + 1 × (−1) + (−1) × 1 + (−1) × (−1) = 1 × 1 + 1 × ( − 1) + ( − 1) × 1 + ( − 1) × ( − 1) Add 1 1 to each side to get 1 = (−1) × (−1) 1 = ( − 1) × ( − 1). 25.6k 4 ...Sounds tough, but once you have mastered the 10× table, it is just a few steps away. Firstly, 11× is mostly easy: from 11×2 to 11×9 you just put the two digits together. 11×2=22, 11×3=33, ..., 11×9=99. And of course 2×, 5× and 10× just follow their simple rules you know already. So it just leaves these to remember: Defintion of proper homotopy https://math.stackexchange.com/questions/2532344/defintion-of-proper-homotopy Let X =R. The homotopy will be from the identity map to itself, so H (0,x)= H (1,x)= x for all x. For each integer n ≥ 1, during the time period [1/(n+1),1/n], the point n∈ X is ...An exponent is the number of times to multiply a number by itself. Write an exponent as a raised number. In the number 2 4 (2 to the exponent 4, or 2 to the power of 4), the ‘4’ is the exponent. The ‘2’ is the number to multiply by itself 4 times over. In this case 2 x 2 x 2 x 2 = 16.How to Use the Calculator. Type your algebra problem into the text box. For example, enter 3x+2=14 into the text box to get a step-by-step explanation of how to solve 3x+2=14.In school you were taught that 1/x+y is not the same as 1/x + 1/y, but for which x and y is it actually true? Watch this video and find out!Subscribe to my c...Just like for the matrix-vector product, the product AB A B between matrices A A and B B is defined only if the number of columns in A A equals the number of rows in B B. In math terms, we say we can multiply an m × n m × n matrix A A by an n × p n × p matrix B B. (If p p happened to be 1, then B B would be an n × 1 n × 1 column vector ... In order to show that T is a function, you need to prove that for each pair of subsets A and B of X there is one and only one subset U of X\times X such that T(A,B)=U, that is, ((A,B),U) \in T ... What is the ''right" norm for the Banach space tensor product in this situation?What is x times 1? Updated: 4/28/2022 Wiki User ∙ 11y ago Study now See answers (13) Best Answer Copy x times 1 is x. Anything times 1 is still that same anything. Wiki User ∙ 11y ago...For Question 1, observe that Z = (B×X)∩V. (Just notice that x ∈ V b means (b,x)∈ V .) Question 2: consider the map f:(B×C)×Pn → (B ×Pn)×(C ×Pn), (b,c,x) ↦((b,x),(c,x)). ... The problem is that in order to remedy the problems and paradoxes of naive set theory, the mathematicians around the turn of the century realised that you ... The numpy.repeat has been mentioned, and that's clearly the equivalent to what you want. But for completenes' sake, there's also repeat from the itertools standard library. . However, this is intended for iterables in general, so it doesn't allow repetions by index (because iterables in general do not have an index definOnline math solver with free step by step solutions to algebra, calculus, and other math problems. Get help on the web or with our math app. Simplify x^ (1/2)*x^ (1/2) x1 2 ⋅ x1 2 x 1 2 ⋅ x 1 2. Multiply x1 2 x 1 2 by x1 2 x 1 2 by adding the exponents. Tap for more steps... x1 x 1. Simplify x1 x 1.Remember, 2x times 4x is the same thing as-- you can rearrange the order of multiplication. This is the same thing as 2 times 4, times x times x. Which is the same thing as 8 times x squared. Remember, x to the 1, times x to the 1, add the exponents. I mean, you know x times x is x squared. So this first term is going to be 8x squared.All the constructions that you used to define the isomorphism are natural/functorial: Given a map X →Y, you have a natural map that respect inclusions, which gives a starting point for all the ... Let X =R. The homotopy will be from the identity map to itself, so H (0,x)= H (1,x)= x for all x. For each integer n ≥ 1, during the time period ... Suppose that Am×nx = 0 has a nontrivial solution x. Prove that, for some row vector z, the equation yA = z has no solution. Assume for contradiction that yA =z has a solution y for all vectors z. Now, multiply on the right by x. This gives, yAx= zx⇒ y(0)= zx⇒ zx = 0. Then, since x is not the zero ...Identify H (A) and H (B) with H (pt). Then f ∗ = (g∗,−g∗), so kerf ∗ = kerg∗. Proof that Sorgenfrey plane is not normal using points x × (-x) They mean all x,−x +ϵ such that x ∈ (a,b) and 0 < ϵ < 1/n; that includes both rational and irrational x. You have a particular n and a non-empty open interval (a,b) ...To write 1 y 1 y as a fraction with a common denominator, multiply by x x x x. 1 x ⋅ y y + 1 y ⋅ x x 1 x ⋅ y y + 1 y ⋅ x x. Write each expression with a common denominator of xy x y, by multiplying each by an appropriate factor of 1 1. Tap for more steps... y xy + x xy y x y + x x y. Combine the numerators over the common denominator.May 25, 2020 · Which expression is equivalent to log Subscript 12 Baseline StartFraction x Superscript 4 Baseline StartRoot x cubed minus 2 EndRoot Over (x + 1) Superscript 5 Baseline EndFraction? 4 log Subscript 12 Baseline x + one-half log Subscript 12 Baseline (x cubed minus 2) minus 5 log Subscript 12 Baseline (x times 1) Free math problem solver answers your algebra, geometry, trigonometry, calculus, and statistics homework questions with step-by-step explanations, just like a math tutor.Dec 18, 2022 · (x) x 1 =x. Why is a number to the first power equal the same number? The following is not a proof or a reason, but it's a demonstrationthat might be intuitively satisfying:'X' mentioned 4 times: X times X times X times X = X to the fourth power'X' mentioned 3 times: X times X times X = X to the third power'X' mentioned 2 times: X times X = X to the second power'X' mentioned 1 time: X = X to ... Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.In algebra, a quadratic equation is any equation that can be rearranged in standard form as where x represents an unknown value, and a, b, and c represent known numbers, where a ≠ 0. An exponent is the number of times to multiply a number by itself. Write an exponent as a raised number. In the number 2 4 (2 to the exponent 4, or 2 to the power of 4), the ‘4’ is the exponent. The ‘2’ is the number to multiply by itself 4 times over. In this case 2 x 2 x 2 x 2 = 16.Understand Negative numbers, one step at a time. Step by steps for fractions, factoring, and prime factorization. Enter your math expression. x2 − 2x + 1 = 3x − 5. Get Chegg Math Solver. $9.95 per month (cancel anytime). See details.Free math problem solver answers your algebra, geometry, trigonometry, calculus, and statistics homework questions with step-by-step explanations, just like a math tutor.Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.How to Use the Calculator. Type your algebra problem into the text box. For example, enter 3x+2=14 into the text box to get a step-by-step explanation of how to solve 3x+2=14. The three integrals from 1 to 2, from 2 to 4, and from 4 to 8 are all equal. Each region is the previous region halved vertically and doubled horizontally. Extending this, the integral from 1 to 2 k is k times the integral from 1 to 2, just as ln 2 k = k ln 2. Calculus. In real calculus, the derivative of 1/x = x −1 is given by the power rule ... 1. negative of (4 squared) is -4² = -(4)² = -(4 × 4) = -16. 2. (negative 4) squared is (-4)² = (-4 × -4) = 16. Use parentheses to clearly indicate which calculation you really want to happen. Squared. A number n squared is written as n² and n² = n × n. If n is an integer then n² is a perfect square.A graduation cap is an example of a mapping cylinder g : X \to Y where X = S^1, Y = [-2,2] \times [-2,2], and g is the inclusion map. Verifying continuity of the deformation retraction of the mapping cylinderFree Square Roots calculator - Find square roots of any number step-by-step By ‘ The law of exponents ‘ , a^n × a^m = a^n+m. Therefore , e^x × e^x = e^x+x = e^2x . Find out how many invertible and diagonal solutions X 2 − 2X = 0 has when X ∈ R3×3. If X is invertible, then multiplying each side of X 2−2X = 0 by the inverse of X gives us that X −2I = 0 and so X = 2I. For the case where X is diagonal, let X ... Dec 18, 2022 · (x) x 1 =x. Why is a number to the first power equal the same number? The following is not a proof or a reason, but it's a demonstrationthat might be intuitively satisfying:'X' mentioned 4 times: X times X times X times X = X to the fourth power'X' mentioned 3 times: X times X times X = X to the third power'X' mentioned 2 times: X times X = X to the second power'X' mentioned 1 time: X = X to ... First we prove an intermediate result. Subtract 0 × 0 0 × 0 from each side to get 0 = 0 × 0 0 = 0 × 0. Now we are ready for the final kill. = 1 × 1 + 1 × (−1) + (−1) × 1 + (−1) × (−1) = 1 × 1 + 1 × ( − 1) + ( − 1) × 1 + ( − 1) × ( − 1) Add 1 1 to each side to get 1 = (−1) × (−1) 1 = ( − 1) × ( − 1). 25.6k 4 ...1.225 × 10 5 + 3.655 × 10 3 = 1.26155 x 10 5. E Notation. E notation is also known as exponential notation. E notation is the same as scientific notation where a decimal number between 1 and 10 is multiplied by 10 raised to some power. In E notation the "times 10 raised to a power" is replaced with the letter e in either uppercase or lowercase.Solve your math problems using our free math solver with step-by-step solutions. Our math solver supports basic math, pre-algebra, algebra, trigonometry, calculus and more.The three integrals from 1 to 2, from 2 to 4, and from 4 to 8 are all equal. Each region is the previous region halved vertically and doubled horizontally. Extending this, the integral from 1 to 2 k is k times the integral from 1 to 2, just as ln 2 k = k ln 2. Calculus. In real calculus, the derivative of 1/x = x −1 is given by the power rule ... 18 seconds. =. 55 seconds. Subtract minutes. 9 minutes is less than 56 minutes so borrow 1 from hours. There are 0 hours so borrow 1 from days. 1 day = 24 hours and 1 hour = 60 minutes, so add 24 to hours, then borrow 1 from hours to leave 23. Add 60 minutes to 9 to get 69. 69 minutes - 56 minutes = 13 minutes.What is x times 1? Updated: 4/28/2022 Wiki User ∙ 11y ago Study now See answers (13) Best Answer Copy x times 1 is x. Anything times 1 is still that same anything. Wiki User ∙ 11y ago...In order to show that T is a function, you need to prove that for each pair of subsets A and B of X there is one and only one subset U of X\times X such that T(A,B)=U, that is, ((A,B),U) \in T ... The numpy.repeat has been mentioned, and that's clearly the equivalent to what you want. But for completenes' sake, there's also repeat from the itertools standard library. . However, this is intended for iterables in general, so it doesn't allow repetions by index (because iterables in general do not have an index definUnderstand Negative numbers, one step at a time. Step by steps for fractions, factoring, and prime factorization. Enter your math expression. x2 − 2x + 1 = 3x − 5. Get Chegg Math Solver. $9.95 per month (cancel anytime). See details.Step-by-Step Examples Algebra Solve for x Calculator Step 1: Enter the Equation you want to solve into the editor. The equation calculator allows you to take a simple or complex equation and solve by best method possible. Step 2: Click the blue arrow to submit and see the result!Symbolab is the best step by step calculator for a wide range of math problems, from basic arithmetic to advanced calculus and linear algebra. It shows you the solution, graph, detailed steps and explanations for each problem.Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.Solve for x sin (x)=1. sin(x) = 1 sin ( x) = 1. Take the inverse sine of both sides of the equation to extract x x from inside the sine. x = arcsin(1) x = arcsin ( 1) Simplify the right side. Tap for more steps... x = π 2 x = π 2. The sine function is positive in the first and second quadrants. To find the second solution, subtract the ...(x) x 1 =x. Why is a number to the first power equal the same number? The following is not a proof or a reason, but it's a demonstrationthat might be intuitively satisfying:'X' mentioned 4 times: X times X times X times X = X to the fourth power'X' mentioned 3 times: X times X times X = X to the third power'X' mentioned 2 times: X times X = X to the second power'X' mentioned 1 time: X = X to ...An exponent is a way to represent how many times a number, known as the base, is multiplied by itself. It is represented as a small number in the upper right hand corner of the base. For example: x² means you multiply x by itself two times, which is x × x. Likewise, 4² = 4 × 4, etc. If the exponent is 3, in the example 5³, then the result ...Simplify x^ (1/2)*x^ (1/2) x1 2 ⋅ x1 2 x 1 2 ⋅ x 1 2. Multiply x1 2 x 1 2 by x1 2 x 1 2 by adding the exponents. Tap for more steps... x1 x 1. Simplify x1 x 1. All the constructions that you used to define the isomorphism are natural/functorial: Given a map X →Y, you have a natural map that respect inclusions, which gives a starting point for all the ... Let X =R. The homotopy will be from the identity map to itself, so H (0,x)= H (1,x)= x for all x. For each integer n ≥ 1, during the time period ... Understand Negative numbers, one step at a time. Step by steps for fractions, factoring, and prime factorization. Enter your math expression. x2 − 2x + 1 = 3x − 5. Get Chegg Math Solver. $9.95 per month (cancel anytime). See details.View solution steps Evaluate x Graph Quiz Polynomial x×1 Similar Problems from Web Search What does X × {0} and Y × {1} mean in this proof? https://math.stackexchange.com/q/2332997 A×B = {(a,b):a ∈ A,b ∈ B}. This is called the Cartesian product. For example {a,b,c}×{0,1} ={(a,0),(b,0),(c,0),(a,1),(b,1),(c,1)} In the context of the proof, ...Solve your math problems using our free math solver with step-by-step solutions. Our math solver supports basic math, pre-algebra, algebra, trigonometry, calculus and more. Sounds tough, but once you have mastered the 10× table, it is just a few steps away. Firstly, 11× is mostly easy: from 11×2 to 11×9 you just put the two digits together. 11×2=22, 11×3=33, ..., 11×9=99. And of course 2×, 5× and 10× just follow their simple rules you know already. So it just leaves these to remember:An exponent is a way to represent how many times a number, known as the base, is multiplied by itself. It is represented as a small number in the upper right hand corner of the base. For example: x² means you multiply x by itself two times, which is x × x. Likewise, 4² = 4 × 4, etc. If the exponent is 3, in the example 5³, then the result ...

In order to show that T is a function, you need to prove that for each pair of subsets A and B of X there is one and only one subset U of X\times X such that T(A,B)=U, that is, ((A,B),U) \in T ... What is the ''right" norm for the Banach space tensor product in this situation?. Codeine promethazine

x times 1

Nov 12, 2018 · Add, subtract, multiply and divide decimal numbers with this calculator. You can use: Positive or negative decimals. For negative numbers insert a leading negative or minus sign before your number, like this: -45 or -356.5. Integers, decimals or scientific notation. For scientific notation use "e" notation like this: -3.5e8 or 4.7E-9. Nov 12, 2018 · Add, subtract, multiply and divide decimal numbers with this calculator. You can use: Positive or negative decimals. For negative numbers insert a leading negative or minus sign before your number, like this: -45 or -356.5. Integers, decimals or scientific notation. For scientific notation use "e" notation like this: -3.5e8 or 4.7E-9. Simplify x^ (1/2)*x^ (1/2) x1 2 ⋅ x1 2 x 1 2 ⋅ x 1 2. Multiply x1 2 x 1 2 by x1 2 x 1 2 by adding the exponents. Tap for more steps... x1 x 1. Simplify x1 x 1. In order to show that T is a function, you need to prove that for each pair of subsets A and B of X there is one and only one subset U of X\times X such that T(A,B)=U, that is, ((A,B),U) \in T ...Free Square Roots calculator - Find square roots of any number step-by-stepMultiply the inside terms: 1 ⋅ x = x. Multiply the last term: 1 ⋅ − 1 = − 1. This is equal to. x2 +x −x −1. The middle terms cancel, and we're left with. x2 −1. Remember, FOIL will work every time, but if we see a product of binomials of the form (a + b)(a −b), we can immediately recognize that it fits the difference of squares ...To add or subtract expressions, expand them to make their denominators the same. Least common multiple of x-1 and x+1 is \left(x-1\right)\left(x+1\right). Simplify 1/ ( square root of x) 1 √x 1 x. Multiply 1 √x 1 x by √x √x x x. 1 √x ⋅ √x √x 1 x ⋅ x x. Combine and simplify the denominator. Understand Negative numbers, one step at a time. Step by steps for fractions, factoring, and prime factorization. Enter your math expression. x2 − 2x + 1 = 3x − 5. Get Chegg Math Solver. $9.95 per month (cancel anytime). See details.Free math problem solver answers your algebra, geometry, trigonometry, calculus, and statistics homework questions with step-by-step explanations, just like a math tutor.To write 1 y 1 y as a fraction with a common denominator, multiply by x x x x. 1 x ⋅ y y + 1 y ⋅ x x 1 x ⋅ y y + 1 y ⋅ x x. Write each expression with a common denominator of xy x y, by multiplying each by an appropriate factor of 1 1. Tap for more steps... y xy + x xy y x y + x x y. Combine the numerators over the common denominator.Multiply (x-1) (x-1) (x − 1) (x − 1) ( x - 1) ( x - 1) Expand (x−1)(x− 1) ( x - 1) ( x - 1) using the FOIL Method. Tap for more steps... x⋅x+x⋅ −1−1x−1⋅−1 x ⋅ x + x ⋅ - 1 - 1 x - 1 ⋅ - 1 Simplify and combine like terms. Tap for more steps... x2 − 2x+1 x 2 - 2 x + 1Compute answers using Wolfram's breakthrough technology & knowledgebase, relied on by millions of students & professionals. For math, science, nutrition, history ...A graduation cap is an example of a mapping cylinder g : X \to Y where X = S^1, Y = [-2,2] \times [-2,2], and g is the inclusion map. Verifying continuity of the deformation retraction of the mapping cylinderIn order to show that T is a function, you need to prove that for each pair of subsets A and B of X there is one and only one subset U of X\times X such that T(A,B)=U, that is, ((A,B),U) \in T ... Free math lessons and math homework help from basic math to algebra, geometry and beyond. Students, teachers, parents, and everyone can find solutions to their math problems instantly.The three integrals from 1 to 2, from 2 to 4, and from 4 to 8 are all equal. Each region is the previous region halved vertically and doubled horizontally. Extending this, the integral from 1 to 2 k is k times the integral from 1 to 2, just as ln 2 k = k ln 2. Calculus. In real calculus, the derivative of 1/x = x −1 is given by the power rule ...Free math lessons and math homework help from basic math to algebra, geometry and beyond. Students, teachers, parents, and everyone can find solutions to their math problems instantly.Compute answers using Wolfram's breakthrough technology & knowledgebase, relied on by millions of students & professionals. For math, science, nutrition, history ....

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