If two resistors with resistances and are connected in parallel, as in the figure, then the total resistance R measured in ohms , is given by 1/R=1/R1+1/R2. If and are increasing at rates of .6 and .7 respectively, how fast is R changing when R1=80 and R2=100?(adsbygoogle = window.adsbygoogle || []).push({});

so i take the derivative of the function which is (-1/R^2)dR/dt=(-1/R1^2)dR1/dt-(1/R2)dR2/dt

and then can calculate R to be 1/180 and i know R1, R2, and dR1/dt=.6 and

dR2/dt=.7

i get 5.052E-9 for dR/dt....which is not right

please help me

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# Homework Help: Related rates of resistors

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