Basic relation table of trigonometric function in senior high school mathematics

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Attention:? (1) You must know formulas of trigonometric functions's deduction ideas in high school mathematics, so that you can clearly "see" the relationship between trigonometric functions and understand the changing forms of formulas of trigonometric functions, such as this formula of trigonometric functions?

Wait a minute.

Therefore, we can freely use these formulas in forward direction, reverse direction and deformation.

⑵ The trigonometric transformation formula is not only used to simplify trigonometric functions, but also to prepare for studying the images and properties of trigonometric functions.

⑶ Basic strategies for constant deformation of trigonometric functions.

① Constant substitution: This method is basic in the formula of trigonometric function, especially the substitution of "1", such as1= cos2θ+sin2θ = tanxcotx = tan45, etc.

② Division of terms and matching of angles. It is also a common method for formulas of trigonometric functions to solve problems, such as splitting term:? ;

Another problem-solving strategy using formulas of trigonometric functions is: matching angles (commonly used angle transformation):? 、? 、

、? 、? Wait a minute.

(3) the number of times of decline and rise. That is, the order of double-angle formula and half-angle formula in trigonometric function is reduced.

(4) Chord (tangent) method. Using the basic relationship of trigonometric function with the same angle, the trigonometric function is transformed into a chord (tangent).

⑤ Introduce an auxiliary angle. Trigonometric functions often see the formula asinθ+bcosθ=? sin(θ+？ ), here is the auxiliary angle? Quadrants are determined by the symbols of a and b, and the value of angle is determined by tan? =? Of course.

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