Determine where θ lies on a graph, cosθ=-3/5 and sin θ0

Question

Determine where θ lies on a graph, cosθ=-3/5 and sin θ>0

Raymond B. · Accepted Answer

it's the angle formed by a ray from the origin to the point (-3,4) and the x axis

in the 2nd quadrant = cos^-1(-3/5) = about 180-53.13

use a calculator with an inverse trig function

the angle

= about 126.87 degrees

= about .705pi radians

= about 2.214 radians

reference angle = about 53.13 degrees = about .927 = almost 1 radian

126.87/180 = .705pi radians

.705(3.141593) = 2.214 radians

Determine where θ lies on a graph, cosθ=-3/5 and sin θ>0