求函数y=(3-sinx)/(2-cosx)的值域

问题描述:

求函数y=(3-sinx)/(2-cosx)的值域
y=(3-sinx)/(2-cosx)变为
sinx-ycosx=3-2y再用辅助角公式接下去怎么做

sinx-ycosx=3-2y变为3-2y=sinx-ycosx=√ (1+y²)[√ 1/(1+y²)]sinx-[y/√ (1+y²)]cosx=√ (1+y²)sin(x- α) —— sinα=y/√ (1+y²),cosα=√ 1/(1+y²)因为 |sin(x- α)|=...