Related Rates: Current & Resistance

Raw Transcript

Hello this is Tom for every step calculus dot com
I’m gonna show you how to do related rates now which is a
pretty technical problem unless you
study it all day and really know it is pretty simple with my programs
this is a actual test problem
On related rates regarding current
and resistance so
let’s get started put index8() here to get my menu
you can go up on the screen to go down to
lower alphabet these are all..I’m going to choose related rates here
and here’s the formula for
voltage, resistance and current v=ir
and they always give you the
voltage change here which is alpha, you have to press alpha
before you enter anything in the my entry lines here and alpha 3
and sometimes they have an increasing or decreasing
I let you choose that, it says decreasing and the volts are alpha 12
and the current is
alpha 48
I always show you what you have entered
you can change it if you want say it’s okay first of all we do the formula to
find out what the resistance is
given the voltage and current and then you write all this down
on your paper, d/dt, your doing, your taking the derivative
of the voltage and the derivative of right side of the equation, i and r
this is the product rule now because remember you got a times sign in-between here
and that’s always the current times the
derivative of the resistance and resistance times the derivative of the
current with regard
to time and then we do the
we plug in the variables all automatic here
here’s the answer .01563
ohms per second, pretty neat huh? every step calculus dot com
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