4050.sagews

f(x) = x^2 / (x^2 + 1)
show(f)
plot(f, (x, -5, 5))

\newcommand{\Bold}[1]{\mathbf{#1}}x \ {\mapsto}\ \frac{x^{2}}{x^{2} + 1}

#var('x')
f(x)=3*x^2
show(f)
plot(f, (x, -1, 1))

\newcommand{\Bold}[1]{\mathbf{#1}}x \ {\mapsto}\ 3 \, x^{2}

#var('x')
f(x) = x*sin(x)
show(f(x))
plot(f,(x, -30, 30))

\newcommand{\Bold}[1]{\mathbf{#1}}x \sin\left(x\right)