Rearranging a trigonometric equation

Question

Okay so the answer to a question needs the numerator to be equal to $(n -\sin(n\pi/2))$ but I have $n\cos(n)-\sin(n)$,

i was wondering if there is someway that i can turn my answer into the required form or have I just made a mistake somewhere in my answer?

Answer 1

You have apparently just made a mistake somewhere in your answer.

Try $n=1$:

• $1 \cos (1) - \sin(1) < 0$, but
• $1 - \sin(1 \pi / 2) = 0$.