Question

prove that cos(pi/3+x)=(cos(x)-√3sin(x))/2​

Answer 1

Step-by-step explanation:

We know that,

cos

(

A

+

B

)

=

cos

A

cos

B

−

sin

A

sin

B

Substituting ,

A

=

π

3

and

B

=

x

,we get

cos

(

π

3

+

x

)

=

cos

(

π

3

)

cos

x

−

sin

(

π

3

)

sin

x

cos

(

π

3

+

x

)

=

1

2

cos

x

−

√

3

2

sin

x

cos

(

π

3

+

x

)

=

1

2

(

cos

x

−

√

3

sin

x

)

So,

Cos (pi / 3 + x) = 1/2 (cos x root 3 sin x), is not true.

i.e.

cos

(

π

3

+

x

)

=

1

2

(

cos

x

3

√

sin

x

)

, is not true .