Question

How do you find out if a function is linear or nonlinear?

Answer 1

If the graph of a function y=f(x) is a straight line then the function is called linear function

if the graph of a function y=f(x) is not a straight line then the function is called non-linear function

Any equation in the form,

$y=ax+b\text{ is a linear function}$

In linear function the heighest power of variable x is always 1

Whereas, in nonlinear function the heighest power of variable x is always greater than 1

example,

$y=ax^2+bx+c$

In the above function, the heighest power of x is 2.

hence, it is a nonlinear function