Question

if A=30show that 4cosA.cos (60-A).cos (60+A)=cos 3A
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Answer 1

Answer:

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Step-by-step explanation:

Answer 2

Answer:

Step-by-step explanation:

Given A=30°

we have to proof:-

4cosA.cos (60-A).cos (60+A)=cos 3A

4cos30.cos(60-30).cos(60+30)=cos 3A

4√3/2*√3/2*0=cos3*30

4*0=cos 90

0=0{value of cos 90=0}

lhs=rhs

hence proofed