well right off A is in quadrant 2
B is in quadrant 4
tan A = sin A/ cos A = 12/13 / -5/13 = - 12/5
tan B = sin B / cos B = -7/25 / 24/25 = -7/24
tan(A-B) = [tan A-tanB] / [1+tan A tan B]
= [ -12/5 + 7/24 ] / [ 1 + 12*7/(5*24) ]
5*24 = 120
so
[ -288 + 35] / [ 120 + 84]
-253 / 204
which is not C
Suppose sin A = 12/13 with 90º≤ A ≤180º. Suppose also that sin B = - 7/25 with -90º≤ B ≤0º. Find tan ( A – B ).
253/325
-323/36
204/325
-253/204
Is it C?
1 answer