Question

当函数y=sinx+根号3cosx,x∈R取最大值时,求自变量x的取值集合S

Answer 1

y=2(sinx*1/2+cosx*√3/2)

=2(sinxcosπ/3+cosxsinπ/3)

=2sin(x+π/3)

所以最大则x+π/3=2kπ+π/2

所以S={x|x=2kπ+π/6,k∈Z}