Question

if tan2A=cos(A-18°)where2A is an acute angle ,find the value of A

Answer 1

We can write tan2A as
cot(90-2A)
Equating=
Cot90-2A =Cot(A-18)
hence,
90-2A=A-18
90+18=3A
108=3A
108/3=A
36=A

Answer 2

Hello friend, good afternoon ☺

Answer:

36°

Step-by-step explanation:

 

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 ☺