# Evaluating an exponential function that models a real-world situation

Staff Emeritus
Science Advisor

## Homework Statement

Suppose that the velocity v(t) (in m/s) of a sky diver falling near the Earth's surface is given by the following exponential function, where time is measured in seconds.

v(t) = 55 (1-e-0.18(t))

Find the initial velocity of the sky diver and the velocity after 6 seconds.
Round your answers to the nearest whole number as necessary.

None.

## The Attempt at a Solution

I don't know what e is, so I can't even attempt this. And it's an online course with no book, just an online program we have to use for everything. It doesn't tell me what e is either.

Dick
Science Advisor
Homework Helper

## Homework Statement

Suppose that the velocity v(t) (in m/s) of a sky diver falling near the Earth's surface is given by the following exponential function, where time is measured in seconds.

v(t) = 55 (1-e-0.18(t))

Find the initial velocity of the sky diver and the velocity after 6 seconds.
Round your answers to the nearest whole number as necessary.

None.

## The Attempt at a Solution

I don't know what e is, so I can't even attempt this. And it's an online course with no book, just an online program we have to use for everything. It doesn't tell me what e is either.

e is Euler's number. http://en.wikipedia.org/wiki/E_(mathematical_constant)

Staff Emeritus
Science Advisor
Dick
Science Advisor
Homework Helper
Thanks. I couldn't even find e in the 'dictionary' part of the program. You'd think they'd give it to you if you have to use it...

Yes, they probably should. Though it's kind of standard.

SteamKing
Staff Emeritus
Science Advisor
Homework Helper
You run into e a lot, especially in connection with natural logs.

d/dx (e^x) = e^x

Integral (e^x) dx = e^x + C

e^(i*pi) + 1 = 0, which relates e, pi, i, 0, and 1 in a single formula [i = SQRT (-1)]