iran-konkur 2020 Q110

iran-konkur · Other · konkur-riazi_1399_specialized_old-curriculum Addition & Double Angle Formulae Addition/Subtraction Formula Evaluation
110. If the terminal side of arc $\alpha$ is in the second quadrant and $\sin\alpha = \dfrac{\sqrt{2}}{10}$, what is the value of $\cos\!\left(\dfrac{11\pi}{4} + \alpha\right)$?
$$-\frac{4}{5} \quad (1) \qquad -\frac{3}{5} \quad (2) \qquad \frac{3}{5} \quad (3) \qquad \frac{4}{5} \quad (4)$$
\textbf{110.} If the terminal side of arc $\alpha$ is in the second quadrant and $\sin\alpha = \dfrac{\sqrt{2}}{10}$, what is the value of $\cos\!\left(\dfrac{11\pi}{4} + \alpha\right)$?

$$-\frac{4}{5} \quad (1) \qquad -\frac{3}{5} \quad (2) \qquad \frac{3}{5} \quad (3) \qquad \frac{4}{5} \quad (4)$$