Polar Derivative Formulas

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Introduction to study about polar derivative formulas:

* In calculus, differentiation is the process of finding the derivative which means measuring how a function changes with respect to its input. The derivative of y with respect to x is given by [(dy)/(dx)] .

* Polar coordinate is a two dimensional coordinate system and it is defined by x = rcos θ, y = rsin θ. To find the derivative [(dy)/(dx)] for polar coordinates, we can use the following formula.

Polar derivative formula:

Study about polar derivative formulas

In this article, we are going to see few example and practice problems which help you to study about polar derivative formulas.

Example problems to study about polar derivative formulas:

Study about polar derivative formulas with example problem 1:

Find derivative of the function r = 8 + 5sin θ

Step 1: Given function

r = 8 + 5sin θ

Step 2: Differentiate the given function r = 8 + 5sin θ with respect to ' θ '

[(dr)/(d theta)] = 5cos θ

Step 3: Substitute all values in the polar coordinate formula

[(dy)/dx] = [((dr)/(d theta) sin theta + r cos theta)/((dr)/(d theta)cos theta - r sin theta)] .

= [((5cos theta) sin theta + (8 + 5sin theta) cos theta)/((5cos theta) cos theta - (8 + 5sin theta)sin theta)]

= [(5cos theta sin theta + 8cos theta + 5sin theta cos theta)/(5cos^2 theta - 8sin theta - 5sin^2 theta)]

= [(10cos theta sin theta + 8cos theta)/(5cos^2 theta - 8sin theta - 5sin^2...

... middle of paper ...

...ta) cos theta)/((5sec^2 theta) cos theta - (5tan theta)sin theta)]

= [((5)/(5))] [(sec^2 theta sin theta + tan theta cos theta)/(sec^2 theta cos theta - tan thetasin theta)]

= [(sec^2 theta sin theta + tan theta cos theta)/(sec^2 theta cos theta - tan thetasin theta)]

Practice problems to study about polar derivative formulas:

1) Find derivative of the function r = 2 + 7sin θ

2) Find derivative of the function r = -4cos 9θ

3) Find derivative of the function r = - 6tan θ

Solutions:

1) [(14cos theta sin theta + 2cos theta)/(7cos^2 theta - 2sin theta - 7sin^2 theta)]

2) [(9sin 9theta sin theta - cos 9theta cos theta)/(9sin 9theta cos theta + cos 9theta sin theta)]

3) [(sec^2 theta sin theta + tan theta cos theta)/(sec^2 theta cos theta - tan thetasin theta)]

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