Answer
$2t$ i $-2t sin (t^2)$ j +$2 sin(t) cos(t)$
Work Step by Step
Take derivatives component-by-component.
Derivative of $t^2$ is $2t$ by power rule, derivative of $cos (t^2)$ is $-2t sin(t^2)$ by trig derivatives and chain rule, derivative of $(sin(t))^2$ is $2 sin(t) cos(t)$ by trig derivatives and chain rule.