Question

if cos x= -0.6 and π<x<3π/2 then tan (x/4)= (a) (1-√5)/2 (b) (√5-1) /2 (c) (√5) /2 (d) (√5+1) /2​

Answer 1

Answer:

Viewed as a right angled triangle

tan

(

x

)

=

5

12

can be thought of as the ratio of opposite to adjacent sides in a triangle with sides

5

,

12

and

13

(where

13

is derived from the Pythagorean Theorem)

So

sin

(

x

)

=

5

13

and

cos

(

x

)

=

12

13