Solve the equation 9 cos (theta) + 4 = 0

Question

9 cos 'theta' + 4 = 0 has two solutions, and it is in degrees (Round to the nearest hundredth).

Answer 1

9cosT +4 = 0

9cosT = -4

cosT = -4/9

T = cos^-1(-4/9) T is in the 2nd or 3rd quadrants

T=116.39 degrees or 180+63.61 = 243.61 degrees

are the 2 solutions you want

but there are an infinite number of solutions

116.39 or 243.61 + 360n where n = any integer