If sin a is equal to 1 by 2 prove that 3 Cos A minus 4 cos cube a is equal to zero
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Solving by assuming 0 < A < π/2.
If sinA = 1/2 then A = π/6
3cosA - 4cos³A
= 3cos(π/6) - 4cos³(π/6)
= 3(√3/2) - 4(√3/2)³
= 3√3/2 - 4(3√3/8)
= 3√3/2 - 3√3/2
= 0
Godspeed!
If sinA = 1/2 then A = π/6
3cosA - 4cos³A
= 3cos(π/6) - 4cos³(π/6)
= 3(√3/2) - 4(√3/2)³
= 3√3/2 - 4(3√3/8)
= 3√3/2 - 3√3/2
= 0
Godspeed!
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