I need help with Find the derivative. Assume that I and R are functions of t.

Dr_fox

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d/dt(IR^2) first i use the chain rule and got 2R(I,t)d/dt(R(I,t) then took the derivative of R(I,t) wich is I2R(I,t)d/dt(R
 

Subhotosh Khan

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d/dt(IR^2) first i use the chain rule and got 2R(I,t)d/dt(R(I,t) then took the derivative of R(I,t) wich is I2R(I,t)d/dt(R
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Please write out the result of your work in mathematics, instead of using only words.
 

HallsofIvy

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d/dt(IR^2) first i use the chain rule and got 2R(I,t)d/dt(R(I,t) then took the derivative of R(I,t) wich is I2R(I,t)d/dt(R
FIRST use the product rule, then use the chain rule. Also you say that "R is a function of t" but repeatedly write "R(I, t)", making it look like R is a function of both I and t. It isn't- R^2 is simply multiplied by I.

\(\displaystyle \frac{dIR^2}{dt}=\frac{dI}{dt}R^2+ I\frac{dR^2}{dt}\)
\(\displaystyle = \frac{dI}{dt}R^2+2IR\frac{dR}{dt}\).
 
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