Question

sinA=5/13find values of cosA tanA

Answer 1

If sina=5/13
Squaring both sides
Sin^2a=25/169(sin^2a=1-cos^2a)
1-cos^2a=25/169
Cos^2a=1+25/169=144/169
Cosa=12/13
Tana=sina/cosa=5/13/12/13=5/12

Answer 2

sin A =5/13

since, sin A= perpendicular/Hypotenuse

therefore,in such a triangle Perp.=5

Hyp=13

so Base= 12 [Pythagoras Theorem]

so cos A =12/13

and tan A = 5/12

hence, cos A tan A = 12*5/13*12

= 5/13

[Alternate Method] : cos A.tan A

⇒ cos A . sin A/ cos A

⇒sin A

⇒5/13