If $\tan \alpha = - \frac { 7 } { 24 }$ and $\beta = \frac { 3 } { 4 }$ for a second-quadrant angle $\alpha$ and a third-quadrant angle $\beta$ , find $\cos ( \alpha + \beta )$
A) $- \frac { 3 } { 11 }$
B) $- \frac { 11 } { 4 }$
C) $\frac { 4 } { 5 }$
D) $\frac { 5 } { 4 }$
E) $\frac { 3 } { 5 }$

Question

Quizplus · Accepted Answer

The Answer is C

If tan⁡α=−724\tan \alpha = - \frac { 7 } { 24 }tanα=−247​

If $\tan \alpha = - \frac { 7 } { 24 }$