Find sinx2 cosx2 and tanx2 from the given information cosx
Find sin(x/2), cos(x/2), and tan(x/2) from the given information. cos(x) = - 24/25, 180 degree
Solution
cos x = - 24 / 25
x lies in 3rd quadrant
applying half angle formula
sin ( x/2 ) = + - sqrt ( 1 - cos x ) / 2
sin ( x/2 ) = + - sqrt ( 1 - ( -24/25 )) / 2 = + - sqrt ( 49/50 ) = +- 7 / sqrt 50
cos ( x/2 ) = + - sqrt ( 1 + cos x ) / 2
cos ( x/2 ) = + - sqrt ( 1 + ( -24/25 )) / 2 = + - 1 / sqrt 50
tan (x/2 ) = + - sqrt ( 1- cos x / 1+cos x )
tan (x/2 ) = + - sqrt ( 49/1 ) = + - 7
