Question

高一三角函数，在线急

已知a为正数，函数f(x)=2*sinax在区间[-π/3,π/4]上是增函数，求a取值范围

Answer 1

-π/2+2kπ<=ax<=π/2+2kπ,其中k为整数再把a除到两边-π/2a+2kπ<=x<=π/2a+2kπ只要使[-π/3,π/4]的范围比-π/2a+2kπ<=x<=π/2a+2kπ小就可以解除a的范围了

Answer 2

x在[-π/3,π/4]增，那么ax应在[-π/2,π/2]增，自己算吧

Answer 3

0.25T=0.25*2π/a <=π/4 既a>=2

Answer 4

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