Question

Se cosx = t, determine o valor de de cos3x

Answer 1

Resposta:

A = = √2/2+cos.3x+cos x/2

x=π/2

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A = √2/2+cos.3(π/2)+cos (π/2)/2

A = √2/2+cos.(3π/2)+cos (π/4)

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π = 180°

3π/2 = (3*180°)/2 = 270°

π/4 = 180°/4 = 45°

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cos(270°) = 0

cos(45°) = √2/2

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A= √2/2+cos.(270)+cos (45)

A= √2/2+0+√2/2

A = 2*(√2/2)

A = √2