To find your error, I looked for the line where you start integrating functions taking negative values. This is the line with . To go from the previous line into this one, you wrote , whereas it should have been .
The question is copied directly from my book but the working is my own.
The answer isn't 0 and I have a feeling that my limits are wrong. I'm not really sure how else to write the limits in order for me to get an answer than isn't 0.
help would be greatly appreciated.
Okay then. I have absolutely no idea how to integrate moduli.
The last one I did was easy and it was just finding the area of two triangles and add them together. I don't think I can do the same for this.
I suppose what i'm asking is "how do you integrate moduli?"
Is this what I need to integrate:
I just noticed something else. In the other post you write "mod cos x < (or equal to) 0" (I haven't figured out how to quote properly). Isn't mod cos x always greater than 0? If any of the values were negative then they wouldn't be needed in the question anyway since it wants the area above the x axis.
I decided to draw a graph of what I needed:
...and it suddenly all made sense! I was supposed to use the symmetry of the graph (integrate the function from 0 to pi/2) and then double it)!!
\m/ MAD SKILLZ! \m/
I got it right! thanks a bundle!