Question

If tan 2a = cot (a-180) where 2a is an acute angle. Find the value of a

Answer 1

 Solution:

( itz 18°, not 180 )✌

It is given that tan2A=cot(A−18°)

 ⇒tan2A=cot(90° −(108° −A))

⇒tan2A=tan(108° −A)        

{°•° cot(90° −A)=tan(A)}

 ⇒2A=108° −A

 ⇒3A=108°

 ⇒A=108°/3 =36°

Thanks ☺