Question

Tan1/√5 is in first quardant then cos @ is

Answer 1

Given:

tanФ = $\frac{1}{\sqrt{5} }$    in first quadrant

To Find:

cosФ

Solution:

In first quadrant cosФ is positive.

Consider a triangle ABC.

AB = 1    BC = $\sqrt{5}$

using Pythogarus theorem AC = $\sqrt{AB^{2} + BC^{2} }$

AC = $\sqrt{6}$

CosФ = $\frac{Base}{hypotenuse}$

          = $\sqrt{\frac{5}{6} }$

hence in first quadrant CosФ = $\sqrt{\frac{5}{6} }$