Question

If $\sec 4A=\text{cosec}(A-{20}^{\circ })$, where $4A$ ia an acute angle , find the value of $A$.

Answer 1

Given, $\sec 4A=\text{cosec}(A-20)$

$\therefore \text{cosec}(90-4A)=\text{cosec}(A-20)$

$\therefore 90-4A=A-20$

$A=\frac{110}{5}$

$\therefore A={22}^o$