Question 932132: Find the exact values of
sin 2u,
cos 2u,
and
tan 2u
using the double-angle formulas.
sin u = −3/5, 3π/2 < u < 2π
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! Find the exact values of
sin 2u,
cos 2u,
and
tan 2u
using the double-angle formulas.
sin u = −3/5, 3π/2 < u < 2π
***
reference angle u is in quadrant IV where cos>0, sin<0
sin u=-3/5
cos u=4/5(working with (3-4-5) reference right triangle in quadrant IV)
..
sin 2u=2sin u*cos u=2*(-3/5)*4/5=-24/25
cos 2u=1-2sin^2(u)=1-2*(9/25)=1-18/25=7/25
tan 2u=sin/cos=-24/7
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