Question

If cos(x)=-4/5 in quadrant II then determine the following sin(x/2),cos(x/2),tan(x/2)

Answer 1

`sin((143.13)/(2) )=0.9487\\\\cos((143.13)/(2) )=0.3162\\\\tan((143.13)/(2) )=2.9999=3\\`

Explanation:

angles in II quadrant are found by solvig 180- ∅ where ∅ is the acute angle

Let us then find the acute angle: in
`cos^(-) ((4)/(5)) = 36.86^(0) \\\\so \ x \ the \ angle \ in \ the \ second \ quadrant \ is \ 180-36.86=143.13^(0) \\\\sin((143.13)/(2) )=0.9487\\\\cos((143.13)/(2) )=0.3162\\\\tan((143.13)/(2) )=2.9999=3\\`