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14.3 Change of Variables, Polar Coordinates. The equation for this surface is ρ = sin φ *cos(2 θ ) (in spherical coordinates). The region R consists of all points between concentric circles of radii 1 and 3 this is called a Polar sector. R. R.
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14.3 Change of Variables, Polar Coordinates The equation for this surface is ρ= sinφ *cos(2θ) (in spherical coordinates)
The region R consists of all points between concentric circles of radii 1 and 3 this is called a Polar sector
R R
A small rectangle in on the left has an area of dydxA small piece of area of the portion on the right could be found by using length times width.The width is rdө the length is drHence dydx is equivalent to rdrdө
In three dimensions, polar (cylindrical coordinates) look like this.
Change of Variables to Polar Form Recall: dy dx = r dr dө
Use the order dr dө Use the order dө dr
Example 2 Let R be the annular region lying between the two circles Evaluate the integral
Problem 18 Evaluate the integral by converting it to polar coordinates • Note: do this problem in 3 steps • Draw a picture of the domain to restate the limits of integration • Change the differentials (to match the limits of integration) • Use Algebra and substitution to change the integrand
Problem 22 Combine the sum of the two iterated integrals into a single iterated integral by converting to polar coordinates. Evaluate the resulting integral.
Problem 24 Use polar coordinates to set up and evaluate the double integral