Sine of 1 Degree

Theorem
where $\sin$ denotes the sine function.

Proof
This is in the form:
 * $a x^3 + b x^2 + c x + d = 0$

where:
 * $x = \sin 1 \degrees$
 * $a = 4$
 * $b = 0$
 * $c = -3$
 * $d = \sin 3 \degrees$

From Cardano's Formula:
 * $x = S + T$

where:
 * $S = \sqrt [3] {R + \sqrt {Q^3 + R^2} }$
 * $T = \sqrt [3] {R - \sqrt {Q^3 + R^2} }$

where:

and:

Thus:

By Sine of 3 Degrees: