Question

what is the area under the curve y(x)= 3e^-5x from x = 1 to x= ∞

Answer 1

$A=\int_1^\infin 3e^{-5x}dx=-\frac{3}{5}e^{-5x}|_{x=1}^{x=\infin}=\frac{3}{5}e^{-5}.$