The improper integral \[\int\limits_0^\infty {{{\rm{e}}^{ – 2{\rm{t}}}}} {\rm{dt}}\] converges to A. 0 B. 1 C. 0.5 D. 2

0
1
0.5
2

The correct answer is $\boxed{\text{A) }0}$.

The improper integral $\int_0^\infty {e^{-2t}} dt$ converges because the function $e^{-2t}$ is continuous and decreasing on $[0, \infty)$, and the limit of the integral as $a \to \infty$ is $0$.

To see this, note that for any $a > 0$, we have

$$\int_a^\infty {e^{-2t}} dt \leq \int_a^\infty dt = a.$$

Taking the limit as $a \to \infty$, we get

$$\lim_{a \to \infty} \int_a^\infty {e^{-2t}} dt \leq \lim_{a \to \infty} a = 0.$$

Since the limit of the integral is less than or equal to $0$, the integral must converge to $0$.