# How do you find the area of a polar function?

## How do you find the area of a polar function?

To understand the area inside of a polar curve r=f(θ), we start with the area of a slice of pie. If the slice has angle θ and radius r, then it is a fraction θ2π of the entire pie. So its area is θ2ππr2=r22θ.

How do you find the area bounded by a polar curve?

To get the area between the polar curve r=f(θ) and the polar curve r=g(θ), we just subtract the area inside the inner curve from the area inside the outer curve.

### What is the element of area in polar coordinates?

The area of a region in polar coordinates defined by the equation r=f(θ) with α≤θ≤β is given by the integral A=12∫βα[f(θ)]2dθ.

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How do you find the radius of a polar curve?

Converting between polar and Cartesian coordinates is really pretty simple. We just use a little trigonometry and the Pythagorean theorem. x and y are related to the polar angle θ through the sine and cosine functions (box). The radius, r, is just the hypotenuse of a right triangle, so r2=x2+y2.

## How do you calculate double integrals in polar coordinates?

In computing double integrals to this point we have been using the fact that dA= dxdy d A = d x d y and this really does require Cartesian coordinates to use. Once we’ve moved into polar coordinates dA≠ drdθ d A ≠ d r d θ and so we’re going to need to determine just what dA d A is under polar coordinates.

How do you find the area element in polar coordinates?

The area element in polar coordinates In polar coordinates the area element is given by dA = r dr dθ. The geometric justiﬁcation for this is shown in by the following ﬁgure. x y. • Δθ r r Δr rΔθ ΔA The small curvy rectangle has sides Δr and rΔθ, thus its area satisﬁes ΔA ≈ (Δr)(r Δθ).

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### How do you find the double integral of a region?

Recall that the definition of a double integral is in terms of two limits and as limits go to infinity the mesh size of the region will get smaller and smaller. In fact, as the mesh size gets smaller and smaller the formula above becomes more and more accurate and so we can say that, dA = rdrdθ d A = r d r d θ

What is the formula for finding the area of an integral?

The formula for finding this area is, Notice that we use r r in the integral instead of f (θ) f ( θ) so make sure and substitute accordingly when doing the integral. Let’s take a look at an example.