# X 2 Y 2 5

To solve this problem, you have to understand the relationship that x and y has with r. r is the radius and has a starting point on the origin with an ending point anywhere on the graph. However, to use r in math, you have to break it into components since the angle provides challenges with calculations. The x component is how far away it is left or right from the origin. The y component is how far it is up or down from the origin. Together, the x and y components with r make a right triangle like so:

The x component is the adjacent side to the angle, so use cosine (Cosine

x= rcos

The y component is the opposite side to the angle, so use sine (Sine

y = rsin

Now that you know what x and y equals, plug them in to the equation.

Square both sides to get

Factor out the

Using the trigonometry identity of cos(2θ)=

(just have to memorize that identity)

Divide both sides by cos(2θ) to isolate r.

Square root it

r=

However since a square root can’t be negative, there are some limits to the domain of cos(2θ).

Normally, cosθ is positive from –

However, since the angle is doubled in cos(2θ), divide by two.

This yields the final domain for this function to be –

**Source: https://socratic.org/questions/how-do-you-convert-x-2-y-2-5-in-polar-form**

*Posted by: soaltugas.net*