If angle \(\theta\) is 135o, evaluate cos\(\theta\)
- \(\frac{1}{2}\)
- \(\frac{\sqrt{2}}{2}\)
-
\(-\frac{\sqrt{2}}{2}\)
- \(-\frac{1}{2}\)
The correct answer is: C
Explanation
\(\theta\) = 135o
Cos 135o = Cos(90 + 45)o
= cos90ocos45o - sin90osin45o
= 0cos45o - (1 x \(\frac{\sqrt{2}}{2}\))
= \(-\frac{\sqrt{2}}{2}\)
There is an explanation video available .