pls solve

Asked by  | 21st Sep, 2009, 10:19: PM

Expert Answer:

we assume that   you want  to prove 2tan10+tan40=tan50

consider tan 50= tan (10+40) = (tan 10+tan 40)/(1-tan 10tan 40)

so tan 50-tan 50tan10tan40 = tan 10+tan 40

tan 50-cot40tan10tan40 = tan 10+tan 40

so tan 50=tan 10+tan 40+tan10 =2tan10+tan40

Answered by  | 24th Nov, 2009, 11:55: AM

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