Trigonometric function deformation formula sin(π/2+α)=cosα.
cos(π/2+α)=-sinα
tan(π/2+α)=-cotα
cot(π/2+α)=-tanα
sin(π/2-α)=cosα
cos(π/2-α)=sinα
tan(π/2-α)=cotα
cot(π/2-α)=tanα
sin(3π/2+α)=-cosα
cos(3π/2+α)=sinα
tan(3π/2+α)=-cotα
cot(3π/2+α)=-tanα
sin(3π/2-α)=-cosα
cos(3π/2-α)=-sinα
tan(3π/2-α)=cotα
cot(3π/2-α)=tanα
The trigonometric function value of special angle remembers the formula of 30, 45 and 60 degrees, and the trigonometric function remembers it firmly;
The denominator chord bisector is three, and the numerator should add a root sign;
One, two, three, three, two, one, three, nine, twenty-seven;
Tangent and sine increase, cosine function decreases.