Let the joint pdf of $X$ and $Y$ be $f(x,y) = 12e^{-4x-3y}, x>0, y>0$.
What is the marginal cdf of $X$? of $Y$?
Am I just supposed to integrate f(x,y) with respect to $x$ or $y$ to get the marginal cdfs?
Edit: Update with work $\begin{align*} f_1(x) = 12 \int_{0}^{\infty}e^{-4x-3y}dy = 12 \lim_{t\to\infty}\int_{0}^{\infty}e^{-4x-3y}dy = 12\lim_{t\to\infty}\bigg[ \frac{-1}{3}e^{-4x-3y}\bigg]_{0}^{t} = -4e^{-4x} \end{align*}
$\begin{align*} f_2(y) = 12 \int_{0}^{\infty}e^{-4x-3y}dx = 12 \lim_{t\to\infty}\int_{0}^{\infty}e^{-4x-3y}dx = 12\lim_{t\to\infty}\bigg[ \frac{-1}{4}e^{-4x-3y}\bigg]_{0}^{t} = -3e^{-4y} \end{align*}$