SOLUTION: VERIFY sin2t-cott= -cotcos2t this from the pre-cal trig identities section. problem deals with the Double ANGLE Formulas. I got really confused started L--R and got stuck. tri

Algebra ->  Trigonometry-basics -> SOLUTION: VERIFY sin2t-cott= -cotcos2t this from the pre-cal trig identities section. problem deals with the Double ANGLE Formulas. I got really confused started L--R and got stuck. tri      Log On


   



Question 873197: VERIFY sin2t-cott= -cotcos2t this from the pre-cal trig identities section.
problem deals with the Double ANGLE Formulas. I got really confused started L--R and got stuck. tried r--L and came up with something but it doesn't look right. Any help would be greatly appreciated.

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
sin(2t)-cot(t) = -cot(t)cos(2t)
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2sin(t)cos(t) = [-cos(t)/sin(t)][cos^2(t)-sin^2(t)]
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2sin(t)cos(t) = [-cos(t)/sin(t)][1-sin^2(t)-sin^2(t)]
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2sin(t)cos(t) - [cos(t)/sin(t)] = (-cos(t)/sin(t))(1-2sin^2(t))
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Multiply each term by sin(t) to get rid of the denominators::
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2sin^2(t)cos(t) - cos(t) = (-cos(t)(1-2sin^2(t))
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2sin^2(t)cos(t) - cos(t) = -cos(t) + 2sin^2(t)cos(t)
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Cheers,
Stan H.
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