Calculus problem help please?

just-ask-just-ask-
in Science & Mathematics

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

  • cidyahcidyah

    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.

  • mr-davidmr-david

    1/2=cos x

    x= pi/3 , 5pi/3

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