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Find the constant term in the expression (x^2-1/x)^9

This problem uses the binomial expansion formula: (x+y) n = k=0 Z n n C k x k y n-k .But lets try to understand where this formula comes from by doing the problem without it to start of with.We have the expr...
VY
Answered by Vincent Y. • Maths tutor
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Express 12.5% as a fraction.

To make a percentage into a fraction you divide it by 100. This means 12.5% is 12.5/100. However, when giving fractions as an answer it needs to be done in the simplest form. To do this you need to find the ...
TG
Answered by Thanu G. • Maths tutor
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Differentiate: tan(2x) cos(x)

Explain the product rule : d/dx ( f(x) . g(x) ) = f'(x).g(x) = g'(x) . f (x) 2. Briefly run through trigonometric derivatives .* cos (x) differentiates to: -sin(x)* tan (x) differentiates to: sec^2 (x) 3. Br...
SD
Answered by Shreyasi D. • Maths tutor
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Rationalise the fraction : 5/(3-sqrt(2))

To rationalise a fraction we have to eliminate the surds in the denominator. We know we can multiply the top and the bottom of a fraction by the same thing, as this is equivalent to multiplying by 1. Notice ...
MM
Answered by Michael M. • Maths tutor
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How to differentiate y=x^3+4x+1 when x=3

First of all you calculate dy/dx. To do this you look at each x individually. For the first x you multiply it by it's power and then minus 1 from the power to get 3x^2. Then multiply the next x by the power ...
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Answered by Leana S. • Maths tutor
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