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Equivalent expression for sinx^3

  • Thread starter synergix
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  • #1
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Homework Statement


Find an equivalent expression for sin3x in terms of function values of x, 2x, 3x, raised only to the first power.


The Attempt at a Solution


stuck! dont know where to begin I am reviewing for my exam right now I remember doing one of these problems before but I cant remember how.

sinx(sinx2)

sinx[(1-cos2x)/2]

am i on the right track?
 

Answers and Replies

  • #2
tiny-tim
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Find an equivalent expression for sin3x in terms of function values of x, 2x, 3x, raised only to the first power.

stuck! dont know where to begin I am reviewing for my exam right now I remember doing one of these problems before but I cant remember how.

sinx(sinx2)

sinx[(1-cos2x)/2]

am i on the right track?
Hi synergix! :smile:

(btw, don't write (sinx2), write either (sinx)2 or sin2x)

Your equation is correct, but I don't think it's what they're asking for …

it has a (sinx)(cos2x) … if you're allowed that, you might as well have (sinx)(sinx)(sinx).

I think they want a sum of first powers, each on its own.

Hint: start at the end …

what is sin(3x) in terms of powers of sinx? :wink:
 

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