Prove that: cos²Θ - sin²Θ = 2cos²Θ

If A + B + C = 180° prove that Sin2A + sin2B – sin2C = 4cosAcosBsinC

If A + B + C = 180° prove that cos2A + cos2B – cos2C = -1 -4cosAcosBcosC

If A + B + C = 180°, Prove that Cos²A + Cos²B - Cos²C = 1 – 2sinAsinBcosC

If A + B + C = 180°, Prove that Sin² (A/2) + sin² (B/2) + sin²(C/2) = 1 – 2sin (A/2) sin (B/2) sin(...

I can't seem to prove these trig identities and would really appreciate help: 1. cosx + 1/sin^3x...

Solve 2cos^2θ/2 = cos2θ for 0º≤θ≤360º. (Hint: Graph each side of the equation and find the points of...

Solve the equation cos2θ = 1/2sinθ 0º≤θ≤90º. (Hint: Graph each side of the equation and determine wh...

Prove L=L

Prove that ; 0⁰C =F-32/1.8

how do you prove something to be true

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