# Math / Excel question

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Tresor
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### Math / Excel question

Hi,

Could a kind sould help a math layman generate an Excel formula for the function that is presented in the picture?

Thanks
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graph of function.png (8.48 KiB) Viewed 225 times

Tresor
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I already have the formula for the above (previous) picture: 1.0001^(-x)

Now I am looking for a formula for the below picture (picture attached).

Help apprecitaed.
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graph of function B.png (7.26 KiB) Viewed 221 times

geizer
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I already have the formula for the above (previous) picture: 1.0001^(-x)

Now I am looking for a formula for the below picture (picture attached).

Help apprecitaed.

Your picture suggests an exponential function. The real world example would be a Voltage (Vc) across a capacitor to which the Input Voltage (V) has been applied.

Take a look at the following link - it is a good tutorial and it contains the formula. The 'Time Constant' (T=RC) determines how fast (or slow) the output goes from 0 to V. In your case V=1. The output will never reach 1, since RC must be greater than zero.

http://www.electronics-tutorials.ws/rc/rc_1.html
http://www.electronics-tutorials.ws/rc/rc_3.html

Regards,
Pavel
Last edited by geizer on 24 Jul 2010, edited 1 time in total.

Tresor
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Hi Pavel,

Solution to the latter picture is: 1-1.0001^(-x)