SOLUTION: Prove that (tanA - tanB)/(1 - tanAtanB) = (cotB - cotA)/cotBcotA - 1

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Question 1186948: Prove that
(tanA - tanB)/(1 - tanAtanB) = (cotB - cotA)/cotBcotA - 1
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
prove:


manipulate left side
%28tan%28A%29+-+tan%28B%29%29%2F%281+-+tan%28A%29tan%28B%29%29 ..........use identity tan%28A%29+=1%2Fcot%28A%29+, tan%28B%29+=1%2Fcot%28B%29+

=%281%2Fcot%28A%29-+1%2Fcot%28B%29%29%2F%281-%281%2Fcot%28A%29%29%281%2Fcot%28B%29%29%29+

=

=..........simplify

=

=%28cot%28B%29+-cot%28A%29%29%2F%28cot%28A%29cot%28B%29+-+1%29+