Question 285166
 change the trig identity of 
tanxcosx = cotx(secx-cosx)
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tan*cos = [cos/sin][1/cos - cos]
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tan*cos = [cos/sin][(1-cos^2)/cos]
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tan*cos = [cos/sin][sin^2/cos]
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tan*cos = [cos/sin][sin/cos][sin]
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tan*cos = [sin/cos][cos/sin][sin]
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tan*cos = [tan(x)][cos]
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Cheers,
Stan H.
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