Question

Find which of the following given numbers is greater (189-191).
sin ${1980}^{\circ }$ or cos ${1980}^{\circ }$?

Answer 1

${1980}^o={180}^o\times 11=11\pi$

Now, $\sin {1980}^o=\sin 11\pi =0$

$\cos {1980}^o=\cos 11\pi =-1$ since it is and odd multiple of $\pi$

Hence, $\sin {1980}^o>\cos {1980}^o$