Integrate e^(-x) dx between 0 and +infinity?

[Jezzybean]

[-e^(-x)] between 0 and +infinity

= 1 - (e^(-infinity))

Right? My mind has gone blank. What do I do now?

[Omstarts]

If a function is raised to a negative (-) power, it becomes a reciprocal of the function i.e. x^-2 is 1/x^2

So, e^-(infinity) is actually 1/e^infinity,

Which is 1/infinity, which tends to zero.

Hence, the answer is 1.

[Omstarts]

If a function is raised to a negative (-) power, it becomes a reciprocal of the function i.e. x^-2 is 1/x^2

So, e^-(infinity) is actually 1/e^infinity,

Which is 1/infinity, which tends to zero.

Hence, the answer is 1.

[Unregistered]

thanks! that was helpful

[Unregistered]

the integral of things that tend to 0 is not always 1..............................