Question

prove that 2(cos^3x-cosxsin^2x)=cos3x+cosx​

Answer 1

Answer:

ans

Step-by-step explanation:

LHS :

cos2xcos

2

x

−cos3xcos

2

9x

=

2

1

[2cos2xcos

2

x

−2cos3xcos

2

9x

]

=

2

1

[cos[(2x+

2

x

)+cos(2x−

2

x

)]−[cos(3x+

2

9x

)+cos(

2

9x

−3x)]]

=

2

1

[cos

2

5x

+cos

2

3x

−cos

2

15x

−cos

2

3x

]

=

2

1

[cos

2

5x

−cos

2

15x

]

=

2

1

[2sin5xsin

2

5x

]

=sin5xsin

2

5x

Answer 2

Answer:

it is your answer

I hope help you