Question

Find sin it cos8 it cos 8 = - 12 is in the third quadrant.04-12OBI08-1ORYReset Selection

Answer 1

Given:

`cos\theta=-(√(2))/(2)`
`\begin{gathered} \theta=cos^(-1)(-(√(2))/(2)) \\ \theta=135^0 \\ \\ In\text{ the third quadrant, } \\ \theta=180+45 \\ \theta=225^0 \end{gathered}`

Hence,

`sin225^0=-(√(2))/(2)`

Therefore, the correct answer is OPTION A.