if the cos inverse of x=pie/3 what is the sin inverse of x ?  TOPIC_SOLVED

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if the cos inverse of x=pie/3 what is the sin inverse of x ?

Postby theshadow on Wed Feb 25, 2009 6:42 pm

if the cos inverse of x= pie/3 what is the sin inverse of x ?
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Postby stapel_eliz on Wed Feb 25, 2009 7:42 pm

theshadow wrote:if the cos inverse of x= pie/3 what is the sin inverse of x ?

I'm going to guess that you don't mean , but just . (The Greek letter used to represent the geometrical value approximated by 3.14159 is spelled "pi"; a "pie" is a baked dessert.)

Use the definition of inverse trig functions: If cos-1(x) = (pi)/3, then cos[(pi)/3] = x. This is what the inverse-cosine function is and does.

Remembering the reference-angle values you've memorized, what is the value of cos((pi)/3)? So what is the value of "x"?

You now need to find sin-1(x). Plug in the value you found for x, and work backwards to the answer, using those same reference-angle values.

If you get stuck, please reply showing how far you have gotten. Thank you! :D
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Re: if the cos inverse of x=pie/3 what is the sin inverse of x ?

Postby theshadow on Wed Feb 25, 2009 11:22 pm

cos((pi)/3) = 1/2, so i'm just taking sin inverse of 1/2?
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Postby stapel_eliz on Thu Feb 26, 2009 1:11 pm

theshadow wrote:cos((pi)/3) = 1/2, so i'm just taking sin inverse of 1/2?

Yup! :D
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