If angle A=30 ,then show that cos3A=4coscubeA -3cosA
Answers
Answered by
2
Given:-A=30
by taking LHS
cos3A
=cos3×30
=cos90
=0
By taking RHS
4cos³A-3cosA
=4cos³30-3cos30
=4×(√3/2)³-3×√3/2
=12√3/8-3√3/2
=3√3/2-3√3/2
=0
hence LHS=RHS
proved
by taking LHS
cos3A
=cos3×30
=cos90
=0
By taking RHS
4cos³A-3cosA
=4cos³30-3cos30
=4×(√3/2)³-3×√3/2
=12√3/8-3√3/2
=3√3/2-3√3/2
=0
hence LHS=RHS
proved
Answered by
8
I think this helps u mark as brainliest
Attachments:
Similar questions