SOLUTION: cos(u) = − 4/5 , 𝜋/2 < u < 𝜋 find sin(2u) cos(2u) tan(2u)

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Question 1168592: cos(u) = − 4/5
, 𝜋/2 < u < 𝜋
find sin(2u)
cos(2u)
tan(2u)
Answer by ikleyn(52787) About Me  (Show Source):
You can put this solution on YOUR website!
.

Use the formulas for trigonometric functions of double argument.


For these formulas,  see the lessons
    - FORMULAS FOR TRIGONOMETRIC FUNCTIONS
    - Trigonometric functions of multiply argument
    - Trigonometric functions of multiply argument - Examples
in this site.