Use the following identities: [tex]sec^2 = 1 + tan^2 \\ \\ sec = \frac{1}{cos} \\ \\ sin^2 = 1 - cos^2[/tex] Also because the angle is in quadrant 3, sin must be negative. Therefore [tex]sin = - \sqrt{1 - \frac{1}{1 + tan^2}}[/tex] Subbing in tan = 0.958 [tex]sin \theta = -0.69178[/tex]
