Question

If tan 2A =cot (A-18),where 2A is an acute angle find the value of A

Answer 1

Answer-

Given- tan2A=cot(A-18) where 2A is an acute angle

solution- tan2A=cot(A-18)

= cot(90-2A)=cot(A-18)

= 90-2A = A-18

= 3A = 108

= A = 36 degree

Answer 2

 Solution:

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°

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