Find $\cos \left(-\frac{7 \pi}{2}\right)$
Answer & explanation
Correct answer: option 4
The concept we use here is :-
cos ( - θ ) = cos θ
Now,
cos ( \(\frac{ - 7π}{2}\) )
= cos ( \(\frac{7π}{2}\) )
= cos ( 4π - \(\frac{π}{2}\) )
= cos ( \(\frac{π}{2}\) )
{ \(\frac{π}{2}\) = 90º }
= cos90º
= 0