Question

if cos x = -3/5 and π < x < 3π/2 , find the value of sin2x ,cos2x ,tan2x

Answer 1

here cos x = -3/5 lies in II quadrant

by Pythagoras theorem
cosx= -3/5
sinx= 4/5
tanx=-4/3
sin2x=sin2×4/5=8/5
cosx= 2×(-3/5)=-6/5
tanx=2×(-4/3)=-8/3