tan(A)tan(B) = [tan(A) + tan(B)] / [cot(A) + cot(B)]
Choose the more complex side, which would be the right hand side.
RHS = [tan(A) + tan(B)] / [cot(A) + cot(B)]
Convert everything to sines and cosines.
RHS = [ sin(A)/cos(A) + sin(B)/cos(B) ] / [ cos(A)/sin(A) + cos(B)/sin(B) ]
To eliminate all fractions, multiply everything by sin(A)cos(A)sin(B)cos(B).
RHS = [ sin^2(A)sin(B)cos(B) + sin(A)cos(A)sin^2(B) ] /
[ cos^2(A)sin(B)cos(B) + sin(A)cos(A)cos^2(B) ]
Factor the numerator and denominator.
RHS = [ sin(A)sin(B) (sin(A)cos(B) + cos(A)sin(B)) ] /
[ cos(A)cos(B) (cos(A)sin(B) + sin(A)cos(B)) ]
Note that sin(A)cos(B) + cos(A)sin(B) is the same as
cos(A)sin(B) + sin(A)cos(B); after some manipulation, we can get them to be the same, because multiplication and addition are commutative, which means we can swap and switch. This means they cancel each other out, leaving us with
RHS = [sin(A)sin(B)] / [cos(A)cos(B)]
Splitting this up into two fractions,
RHS = [sin(A)/cos(A)] [sin(B)/cos(B)]
And, by definition
RHS = tan(A)tan(b) = LHS
2007-02-03 07:25:44
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answer #1
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answered by Puggy 7
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i think of it would be people. in the early component of our lives, we are transferring forward, growing to be, studying, changing. As we enter previous age, we detect ourselves transferring backward, remembering much less, usually no longer waiting to look after ourselves (transferring backwards in direction of being like a newborn back). while it rains, we stroll extra rapidly, while that's dry we stroll extra slowly. I do wish you will post the respond as quickly as you get carry of it!
2016-12-17 08:40:43
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answer #2
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answered by ? 3
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