Not all formulas are necessary to solve every exercise. Following formulas are sufficient to calculate the trigonometric function any angle. Only these formulas will be use. sin(k*360°+α) = sinα, cos(k*360°+α) = cosα, tan(k*180°+α) = tanα, cot(k*180°+α) = cotα, k - any integer, sin(-α) = -sinα, cos(-α) = cosα, tan(-α) = -tanα, cot(-α) = -cotα, sin(180°-α) = sinα, cos(180°-α) = -cosα, tan(180°-α) = -tanα, cot(180°-α) = -cotα, sin(180°+α) = -sinα, cos(180°+α) = -cosα, tan(180°+α) = tanα, cot(180°+α) = cotα. All trigonometric formulas.