Question

Can someone please help me

Answer 1

Answer:

see explanation

Step-by-step explanation:

$\frac{3\pi }{4}$ is an angle in the second quadrant where sin > 0 and cos < 0

cos($\frac{3\pi }{4}$ )

= cos (π - $\frac{3\pi }{4}$ )

= - cos ($\frac{\pi }{4}$ )

= - $\frac{\sqrt{2} }{2}$

and similarly

sin ($\frac{3\pi }{4}$ )

= sin ($\frac{\pi }{4}$ )

= $\frac{\sqrt{2} }{2}$