Question

Which function is increasing?? :)

Answer 1

`\large\boxed{B.\ f(x)=4^x}`

Explanation:

Exponential function
`f(x)=(a)^x` is

increasing if
`a > 1\to a\in(1,\ \infty)`

decreasing if
`0 < a < 1\to a\in(0,\ 1)`

`A.\ f(x)=\left((1)/(4)\right)^x\to a=(1)/(4)\in(0,\ 1)\to\text{decreasing}\\\\B.\ f(x)=4^x\to a=4\in(1,\ \infty)\to\text{increasing}\\\\C.\ f(x)=(0.4)^x\to a=0.4\in(0,\ 1)\to\text{decreasing}\\\\D.\ f(x)=\left((1)/(2)\right)^x\to a=(1)/(2)\in(0,\ 1)\to\text{decreasing}`