Answer:
cot(A-B) = 3/19
Explanation:
The formula for cot(A-B) = (Cot A Cot B + 1 ) / (Cot B - Cot A)
we know that cot A = 1/ Tan A
Given
tan A=2/3
therefore cot A = 1/ tan A = 1/2/3 = 3/2
tan B= -3/5
cot B = 1/ tan B = 1/-3/5 = -5/3
Thus,
(Cot A Cot B + 1 ) = (3/2)*(-5/3 )+ 1 = -5/2 +1 = (-5+2)/2 = -3/2
(Cot B - Cot A) = -5/3 -3/2 = (-5*2) + (-3*3) / 2 = -10 -9/2 = -19/2
Thus,
cot(A-B) = (Cot A Cot B + 1 ) / (Cot B - Cot A) = -3/2 / -19/2 = 3/19
Thus,
cot(A-B) = 3/19