Question

Angles a and b are in the fourth quadrant. If sin a = -12/13 and cos b = 20/29 find tan (a+b)

Answer 1

tan (a+b) = 2.27 or (345/152)

Explanation:

a and b are in the fourth quadrant

sin a = -12/13 tan a = - 12/5 = - 2.4

cos b = 20/29 tan b = - 21/20 =.1.05

tan (a+b) = (tan a + tan b) / (1 - tan a * tan b)

= (-2.4 + - 1.05) / ( 1 - (-2.4)*(-1.05))

= (-3.45) / (-1.52)

= 2.27