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Tuesday, September 17, 2013

To maximize any quantity we should differentiate that with respect to variable one and equate to zero,why?

To maximize any quantity we should differentiate that with respect to variable one and equate to zero,why?

To obtain the maximum point for a function, we should differentiate it with respect to variable one and equate it to zero because once a quantity is at its maximum/minimum value there wont be any further change so the change (differentiation) is zero.

For example, in dc motor to obtain the condition for maximum power developed by armature,the power equation is differentiated with respect to variable quantity Ia and equated to zero.

(i.e) power developed in armature, Pm = VI-Ia^2Ra


To get that condition for maximum power developed, we should do, dPm / dIa =0 ( Ia is varying quantity(because as Ia varies Pm varies).

dPm / dIa =0  (under this condition, there wont be any further change of Pm with respect to Ia(i.e the change is zero)

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