Question

Qual a resolução da integral
3t cos(3t²)dt

Answer 1

$y= \int {3tcos(3t^2)} \, dt \\ \\ x=3t^2 \rightarrow dx=6t~dt \\ \\ y= \int\ {( \frac{dx}{2} )cos(x)} \\ y= ( \frac{1}{2}) \int\cos(x)~dx} \\ \boxed {y=( \frac{1}{2}) sin(3t^2)}$