Question 511104
Find 
(a) tan(x+y)
= [tan(x)+tan(y)]/[1-tan(x)*tan(y)] 
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= [7/3 + 3/4]/[1 - (7/3)(3/4)]
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= [37/12] / [1 - (7/4)]
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= (37/12)/(-3/4)
--
= (37/12)*(-4/3) 
= -36/9
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(b) tan(x-y)
= [tan(x)-tan(y)]/[1+tan(x)*tan(y)] 
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= [7/3 - 3/4]/[1 + (7/3)(3/4)]
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= [18/12] / [1 + (7/4)]
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= (3/2)/(11/4)
--
= (3/2)*(4/11)
---- 
= 6/11
 
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tan x = 7/3, 0<x<1/2pi ; tan y = 3/4, 0<x<1/2pi 
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Cheers,
Stan H.