三角恒等变换是指利用同角公式、诱导公式、两角和与差的三角函数公式、和差化积与积化和差公式、万能公式等对三角式做各种有目的的变形.变形中主要涉及角、函数、名、结构、运算方式的变换,其技巧常有差异分析、化异为同、辅助角、三角代换、和差配凑、幂指变换等.三角恒等变 Triangle equal transformation refers to the use of the same angle formula, the induction formula, trigonometric function formulas of two angles and difference, and the product of the difference and product of integration and difference formula, the universal formula for the triangle to do all kinds of purpose deformation. Mainly involves the transformation of angle, function, name, structure and operation mode, and its skills are often analyzed in different ways, the same, the assistant angle, the triangle substitution, the difference distribution, the power index transformation, etc. The triangular constant change