Question

If tan theta equal to one by root 5 and theta lies in the first quadrant the value of cos theta is

Answer 1

tanx= 1/√5

sec²x-tan²x= 1

sec²x= 1+ tan²x

sec²x= 1+ (1/√5)²

sec²x= 1+ 1/5

sec²x= 6/5

secx= √(6/5)

cosx= √(5/6)