Question

What is the value of the expression: $\cot (-{90}^o)$?

• A. $0$
• B. $-1$
• C. $1$
• D. Cannot be determined

Answer 1

The correct option is A $0$

$cot(-{90}^o)=\frac{\cos (-{90}^o)}{\sin (-{90}^o)}=\frac{\cos {90}^o}{-\sin \left({90}^o\right)}=0$

Therefore, the value of $\cot (-{90}^o)=0$.

So, option A is correct.