Question

How to find cos(a) if tan (a) = 0.5 and a is in the III quadrant

Answer 1

Answer:

hey

Step-by-step explanation:

tana=5/10

tan a=1/2

I\

1 I \ x

I \

I__a\

2

Let unknown side be x

angle be a

using pythagorus theorem,1²+2²=x²

x²=5

x= √5,-√5

cos a= 2/√5

but a is in quadrant III ,Cos is negative

cos a= -2/√5