why we take derivative of the function?

Question

.sam. · Answer

There's a LOT of things you can do with derivative, http://en.wikipedia.org/wiki/Derivative

anonymous · Answer

any example?

.sam. · Answer

Inflection point

anonymous · Answer

well i am jst asking what is its use  in our daily life?

callisto · Answer

finding that rate of change... for example, the velocity of a car can be found by ds/dt

.sam. · Answer

yes

.sam. · Answer

Lets say if you were to build a square fence and wanted to use the least amount of fencing possible to make that fence of 1000 square feet,then the derivative can be helpful

anonymous · Answer

how?

anonymous · Answer

you can use calculus to work out the closest distance between moving objects

.sam. · Answer

Example
Find dimensions of recangle of area 1000, whose peimeter is small as possible,
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Minimum perimeter: P=2x+2y
Area,A=xy, 
y=1000/x

P=2x+1600/x
Derivative of P, 2-2000/x^2 
2-2000/x^2=0
x^2=1000
x=sqrt(1000)