Question

If cos 9A= sin A and 9A<90 find the value of tan 5A

Answer 1

cos 9A = sin A 

cos 9A = cos (90-A) 

9A = 90 - A 

10A = 90 

A = 9 

So tan 5A = tan 45 = 1 

Answer 2

U can solve either of mine or his way....both r correct.............