Browse Questions

# State true or false for the following : The complex number $\;cos \theta + i sin \theta\;$ can be zero for some $\;\theta$

$(a)\;True\qquad(b)\;false$

Explanation :
False , because $\;cos \theta + i sin \theta =0\;$ => $\;cos \theta=0\;$ and $\;sin \theta=0\;$. But there is no value of $\;\theta\;$ for which $\;cos \theta\;$ and $\;sin \theta\;$ both are zero.