The definition domain of trigonometric function is: sin (x), the definition domain of cos (x) is r, and the range of values is [- 1,1]; The definition domain of tan(x) is that X is not equal to π/2+kπ, and the value domain is r; Cot(x) is defined as x but not equal to kπ, and its range is r; The range of y = a sin (x)+b cos (x)+c is [c-√ (a&; sup2+b & amp； sup2)，c+√(a & amp； sup2+b & amp； sup2)]。

Memory formula

Trigonometric functions are functions, and quadrant symbols are labeled. Function image unit circle, periodic parity increase and decrease.

The same angle relation is very important, and both simplification and proof are needed. At the vertex of a regular hexagon, the string is cut from top to bottom.

Write the number 1 in the middle to connect the vertex triangles. The sum of squares of a downward triangle, the reciprocal relationship is diagonal.

Any function of a vertex is equal to the division of the last two. The inductive formula is good, negative positive and then big and then small.

It is easy to look up the table by turning it into an acute angle, and it is essential to simplify the proof. Half of an integer multiple of two, with the odd remainder unchanged.

The latter is regarded as an acute angle, and the sign is judged as the original function. The cosine of the sum of two angles is converted into an angle for evaluation.

Cosine product minus sine product, angular deformation formula. Sum and difference products must have the same name, and the complementary angle must be renamed.

The calculation proves that the angle is the first, pay attention to the name of the structural function, the basic quantity remains unchanged, and it changes from complexity to simplicity.