<PRE><B>Question 856287</B>
A and B are positive acute angles. If sinA=4/5 and cosB=8/17, find the value of tan(A-B)
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If sin(A) = 4/5, cos(A) = sqrt[5^2-4^2]/5 = 3/5
Then tan(A) = sin/cos = 4/3
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If cos(B) = 8/17, sin(B) = sqrt(17^2-8^2]/17 = 15/17
Then tan(B) = sin/cos = 17/8
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Your Problem:
tan (A-B) = [(4/3)+(15/17)]/[1-(4/3)(15/17)]  = -12.56
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Cheers,
Stan H.</PRE>