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# OCR C4 Intergration of trig question (rep+) watch

1. Hey guys, I have been trying this and I can't do it!

The curves y=sinx and y=cosx and the x axis enclose a region.

a) Find the area of the shaded region
b)find the volume generated when this region is rotated about the x axis.

Okay so a) If you drew this out, you would see that you have limits of 1/2pi and 0 for the graph of cosx

Therfore intergrating cosx with limits 1/2pi and 0 I get 1

now this is where I am stuck.... sinx and cosx intercept at tanx=1, which is 1/4pi.

Now if i took the limits to be 0 and 1/4pi for intergrating sinx, I get -2sqrt2 divided all by 2.

Now do I add 1 or takeaway 1?

this is really annoying me!
I dont know what to take as limits when intergrating sinx, as i want to get rid of the bit above.... if anyone can draw a graph that would help alot to the people trying to solve the problem

Thanks guys
2. Isn't the region you want: the area under sinx from x=0 to x=pi/4, plus the are under cosx from x=pi/4 to x=pi/2 ?

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