Calculus problem help please?
I got this question wrong on my test. Can you please show me how to get the answer? I would appreciate any help!
Which of the following represents the area inside r = 5, but outside r=10cos(θ)?
I took a screen cap of the answer choices they gave me:
http://i47.tinypic.com/23u3eib.png
Update:
@Mr. David, that still doesn't help me find the rest of the answer. Thanks though.
Comments
I haven't solved it.
But this is a graph and the area they are looking for.
10 cos(theta)=5
cos(theta)=5/10 = 1/2
theta = pi/3, 5pi/3
I have enclosed a link that may be of use.
Click here for the area picture:
http://s1169.photobucket.com/albums/r502/chibuckt/...
In the above link, ignore the 2pi etc. It got in there somehow while I was scanning.
The left circle is r=5
The right circle is r=10 cos(theta)
The shaded area is the area that we want.
1/2=cos x
x= pi/3 , 5pi/3