Question

if tan theta = 1/root5 and theta lies in yhe first quadrant, the value of cos theta is?
1) whole root 5/6
2) - while root 5/6
3) 1/root6
4) -1/root6

Answer 1

Since tan theta=p/b=1/√5
So p=1,and b=√5
we know that h²=p²+b²
h=√(1²+√5²)
h=√26
so cos theta=b/h
=√5/√6(as theta is in first quadrant cos theta is positive)

P.S.
use this rule to check the sign of trigonometric functions-
All sin tan cos(in 1st quad all +ve,in 2nd quad only sin and cosec +ve,in third quad only tan and cot +ve,and in 4th only cos and sec +ve)

Answer 2

Answer:

hope it helps u sir ❤❤❤❤❤❤❤❤