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# Trigonometry watch

2(sec x-1)=tan x, and x is not a multiple of pie/2, prove that tan (x/2) = 1/2 and deduce the values of sin x and cos x.

Ans: sin x = 4/5 cos x = 3/5
2. Sorry you've not had any responses about this. Are you sure you’ve posted in the right place? Posting in the specific Study Help forum should help get responses.

I'm going to quote in Tank Girl now so she can move your thread to the right place if it's needed.

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(Original post by Tank Girl)
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3. (Original post by Zoshii)
2(sec x-1)=tan x, and x is not a multiple of pie/2, prove that tan (x/2) = 1/2 and deduce the values of sin x and cos x.

Ans: sin x = 4/5 cos x = 3/5
What have you tried so far? This drops out quite nicely using standard trig identities and rearrangement

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