$\left(6x+9\right)$

$\frac{d}{dx}\cos\left(x+y\right)=\sin\left(x\right)\cdot\sin\left(y\right)$

$\lim_{t\to\infty}\left(\frac{4t^2+7}{5t^3+3}\right)$

$23-\left(-10\right)$

$\frac{\left(1+\theta\right)}{\theta}=\theta$

$\int_2^3\:\frac{3x^3-x^2+6x-4}{x^4+x^2-2}dx$

$3r\:+6$