Question

Find the exact value of the expression-

$\tan 12°-cot78°$

Short answer

The required value is,

$\tan 12°-cot78°=0$

Step-by-step solution

Step 1. Given information

Given expression $\tan 12°-cot78°$

Step 2. Calculation

Solving the given expression,

$\tan 12°-cot78°$

localid="1647098202915" $=\tan (90°-78°)-cot78°$ -------(complementary angle, $\tan (90°-A)=cotA$)

$$\begin{gathered} =cot78°-cot78° \\ =0 \end{gathered}$$