If the S in A 35 and pi2 Solutionsin A 35 A lies in 2nd q

Solution

sin A = 3/5 , A lies in 2nd quadrant

cos b = -12/13 , B lies in 3rd quadrant

cos A = (5^2 - 3^2 ) / 5 = - 4 / 5

sin B = (13^2 - 12)^2 / 13 = -5/13

a) cos (A-B) = cos A cos B + sin A sin B

plugging the values in the formula

cos (A-B) = (-4/5)(-12/13) + (3/5)(-5/13)

= 48 / 65 - 15 / 65

= 33/65

b) sin (A+B) = sin A cos B + cos A sin B

plugging the values

sin (A+B) = (3/5)(-12/13) + (-4/5)(-5/13)

= -36/65 + 20/65

= -16/65