Is sin(4x)=-2sin(2x) ?

The answer to whether sin(4x)=-2sin(2x) is False

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prove sin(4x)=-2sin(2x)

prove

sin (4 x) = - 2 sin (2 x)

False

Solution steps

sin (4 x) = - 2 sin (2 x)

Show that the two sides are not equal

For

sin (4 x) = - 2 sin (2 x)

plug in

x = 1

sin (4 \cdot 1) = - 0.75680 \dots

sin (4 \cdot 1)

Refine to a decimal form

= - 0.75680 \dots

- 2 sin (2 \cdot 1) = - 1.81859 \dots

- 2 sin (2 \cdot 1)

Refine to a decimal form

= - 1.81859 \dots

The two sides are not equal

\Rightarrow False

\frac{sin ( a )}{1 - cos ( a )} - cot (a) = csc (a)

2 sin^{2} (a) + cos^{2} (a) = 1 + sin^{2} (a)

\frac{cos ^{2} ( θ )}{1 + sin ( θ )} + sin (θ) = 1

sin (2 t) = 2 sin (t) cos (t)

sin (2 a) + cos (a) = cos (a) (2 sin (a) + 1)