Calc Integral: |sinx-cos2x| from 0 to \pi/2

semc
Messages
364
Reaction score
5
\int^{\pi/2}_{0}|sinx-cos2x| dx
Hi guys i can't seem to get the correct answer for this. What i did was draw the graph of sinx and cos2x and for 0 to \pi/6 i use cos2x-sinx since cos2x is higher. From \pi/6 to \pi/2 i use sinx-cos2x. However i am not able to get the same answer as my book can someone tell me is this the way to do integrals involving the absolute value?
 
Last edited:
Physics news on Phys.org
You've split the integral up correctly. Your problem must be in evaluating the two integrals.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top