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Find R and a such that 7*cos(x)+3*sin(x)=Rcos(x-a)

Use the cosine trig identity, cos(a-b)=cos(a)cos(b)+sin(a)sin(b) ,to write Rcos(x-a) as R(cos(x)cos(a)+sin(x)sin(a)).Now we can equate the coefficients of the sines and cosins on either side of the equation ...
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Answered by Darius Y. Maths tutor
7235 Views

why is the number e important?

When we work with circles, one of the most popular things to pop up is pi. We know that for any circle the circumference divided by the radius gives pi, without failure always. Pi is a number that’s been fou...
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Answered by Sam V. Maths tutor
3379 Views

Why does the chain rule work?

One of the best ways to view dy/dx is as a fraction. When we have y=f(g(x)), we need to make a substitution u=g(x) to find dy/dx. This leaves us y=f(u) and u=g(x). Differentiating said terms leaves us with d...
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Answered by Sam V. Maths tutor
3554 Views

How do we factorise?

The general form of factorising is that if we have ab+ac, we can rewrite this as a(b+c). We multiply each statement inside the bracket by a. So we’re effectively ripping out common terms. We are dividing b a...
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Answered by Sam V. Maths tutor
3481 Views

Separate (9x^2 + 8x + 10)/(x^2 + 1)(x + 2) into partial fractions.

First, we find the form of the two fractions we're going to get. As one denominator has a power of 2, and the other a power of 1, our answer will be of the form: [(Ax+B)/(x 2 +1)] + [C/(x+2)]. If we make thi...
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Answered by Laura U. Maths tutor
5021 Views