How Do You Solve for Sin(theta/2) Using the Half Angle Formula?

AI Thread Summary
To find sin(theta/2) given sin(theta) = 3/5, the half-angle formula is applied: sin(theta/2) = sqrt((1 - sin(theta)) / 2). Substituting sin(theta) into the formula results in sin(theta/2) = sqrt((1 - 3/5) / 2). This simplifies to sqrt((2/5) / 2), which further reduces to sqrt(1/5). The user ultimately realizes their mistake and resolves the problem after some confusion.
daliberataaa!
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Homework Statement


given that sin theta = 3/5, 0 < theta < pi/2 find sin theta/2


Homework Equations


http://www.intmath.com/Analytic-trigonometry/sinalphaon2.gif


The Attempt at a Solution


I appologize that I don't know how to use all the symbols on a keyboard (square roots, etc)
But I have so far gotten it to :

square root of 1-3/5 all over 2. I have a sample of this same problem in my book, but they don't explain the next step. Suddenly this problem from here just turns into square root of 1/5...can someone please explain how they got to there?

Thank you all.
 
Last edited by a moderator:
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ok i feel like the biggest idiot in the world...i got it.

I blame sleep deprivation...haha.
 

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