Question

求使下列函数取得最大值和最小值的自变量x的集合

Answer 1

k为整数

（1）ymax

cos(π/3)x=-1,π+2kπ=(π/3)x,x=6k+3

ymin

.=1 ,2kπ=(π/3)x ,x=6k

(2)ymax

sin(2x+π/4)=1,π/2+2kπ=2x+π/4,x=π/8+kπ

ymin

.=-1,3π/2+2kπ=2x+π/4,x=5π/8+kπ