Question 461084
A nonlinear equation is not necessarily something raised to a power; it is simply an equation that is not represented by a line.


In addition to polynomial curves, the following functions are non-linear:

Trigonometric function

f(x) = sin(x)
{{{graph(200,200,-10,10,-10,10, sin(x))}}}

f(x) = tan(x)

{{{graph(200,200,-10,10,-10,10, tan(x))}}}


Logarithmic or exponential function

f(x) = ln x

{{{graph(200,200,-10,10,-10,10, ln(x))}}}


Of course there are countless other examples.