Is cos(θ)-sin(θ)sin(2θ)=cos(θ)cos(2θ) ?

The answer to whether cos(θ)-sin(θ)sin(2θ)=cos(θ)cos(2θ) is True

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prove cos(θ)-sin(θ)sin(2θ)=cos(θ)cos(2θ)

prove

cos (θ) - sin (θ) sin (2 θ) = cos (θ) cos (2 θ)

True

Solution steps

cos (θ) - sin (θ) sin (2 θ) = cos (θ) cos (2 θ)

Manipulating left side

cos (θ) - sin (θ) sin (2 θ)

Rewrite using trig identities

= \frac{cos ( θ ) + cos ( 3 θ )}{2}

Manipulating right side

cos (θ) cos (2 θ)

Rewrite using trig identities

= \frac{cos ( θ ) + cos ( 3 θ )}{2}

We showed that the two sides could take the same form

\Rightarrow True

1 + (cot (A))^{2} = \cdot (csc (A))^{2}

\frac{sin ( x ) \cdot cos ( x )}{tan ( x )} = cos^{2} (x)

\frac{1}{cos ^{2} ( x )} = 20

\frac{1 - cos ^{2} ( a )}{cos ^{2} ( a )} = tan^{2} (a)

cos^{2} (9 0^{\circ}) - sin^{2} (9 0^{\circ}) = cos (18 0^{\circ})

Is cos(θ)-sin(θ)sin(2θ)=cos(θ)cos(2θ) ?
The answer to whether cos(θ)-sin(θ)sin(2θ)=cos(θ)cos(2θ) is True