Formula - Composite functions

To find the formula for $fg(x),$ we substitute $g(x)$ into $f.$

Consider the functions

egin{align*} &f: x mapsto 2x+3, && extrm{for } x in mathbb{R}, x geq 0, \ &g: x mapsto x^2, && extrm{for } x in mathbb{R}. end{align*}

{fg(x) = f(x^2)}

egin{align*} &f: x mapsto 2x+3, && extrm{for } x in mathbb{R}, x geq 0, \ &g: x mapsto x^2, && extrm{for } x in mathbb{R}. end{align*}

{gf(x) = g(2x+3)}