Question

if value of theta equal to 30°
Then prove 4 cos ^3 theta - 3 cos theta = cos 3 theta​

Answer 1

Answer:

• cos(3×30°)=4cos^3(30°)-3cos(30°)

cos 90°=4cos^3(30°)-3cos(30°)

 0=4(_/3÷2)^3-3×_/3÷2

0=(12_/3)/8-(3_/3)/2

0=(3_/3)/2-(3_/3)/2

0=0

hence proved.

Step-by-step explanation:

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