Math Problem Statement

Put into polar coordinates, y^2=4ax, with the origin as a pole.

Solution

The equation y2=4axy^2 = 4ax is the equation of a parabola in Cartesian coordinates. To convert this into polar coordinates, we use the relationships:

x=rcosθandy=rsinθx = r \cos \theta \quad \text{and} \quad y = r \sin \theta

Substitute these into the given equation:

(rsinθ)2=4a(rcosθ)(r \sin \theta)^2 = 4a(r \cos \theta)

This simplifies to:

r2sin2θ=4arcosθr^2 \sin^2 \theta = 4ar \cos \theta

Now, divide both sides by rr (assuming r0r \neq 0):

rsin2θ=4acosθr \sin^2 \theta = 4a \cos \theta

Therefore, the equation in polar coordinates is:

r=4acosθsin2θr = \frac{4a \cos \theta}{\sin^2 \theta}

This is the polar form of the parabola y2=4axy^2 = 4ax with the origin as the pole.

Would you like further details or have any questions?


Here are 5 related questions:

  1. How do you convert a general conic section to polar coordinates?
  2. What is the geometric interpretation of this parabola in polar coordinates?
  3. How would you find the directrix of the parabola y2=4axy^2 = 4ax in polar form?
  4. What happens to the equation if you move the origin to a different point?
  5. How can this transformation help in graphing polar curves?

Tip: Always remember to substitute xx and yy with rcosθr \cos \theta and rsinθr \sin \theta respectively when converting between Cartesian and polar coordinates.

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Math Problem Analysis

Mathematical Concepts

Polar Coordinates
Parabolas
Coordinate Geometry

Formulas

x = r cos θ
y = r sin θ
r = (4a cos θ) / sin^2 θ

Theorems

Conversion between Cartesian and Polar Coordinates

Suitable Grade Level

Grades 10-12