Free-form input works fine but with graphics

[chprof]

Hi there,
I’m new to Mathematica, learning for 2 days through the Hands-on videos.

Everything I reproduce from the given examples leads to the expected result, but the graphics generated through free-form input.

Please help me figure out what’s wrong with my attempts, displayed below.
Thank you for giving a leg up.

[cadrin (Simon Cadrin)]

Plot[Sin/x, {x, 0, 3*Pi}]

Integrate[Cos[2*x], x]

Plot[1/2 Sin[2 x], {x, -Pi, Pi}]