Question

设幂函数f(x)的图像过p(3,27开4次),g(x)过q(-8,-2),求不等式f(x)小于等于g(x)的解集

Answer 1

f(x)=x^a

图像过p(3,27开4次),

3^a=27^(1/4)=[(3^3)]^(1/4)=3^(3/4)

所以a=3/4〉0

g(x)=x^b

图像过q(-8,-2),

(-8)^b=-2

(-2)^3b=(-2)^1

3b=1

b=1/3

f(x)