Math Problem Statement

Write the following Cartesian curve in polar form: y = 2x - 1

Solution

To convert the Cartesian equation y=2x1y = 2x - 1 into polar coordinates, we need to use the relationships between Cartesian and polar coordinates:

x=rcosθx = r \cos \theta y=rsinθy = r \sin \theta

Step 1: Express y=2x1y = 2x - 1 in terms of xx and yy

The equation is already in Cartesian form, so we have:

y=2x1y = 2x - 1

Step 2: Substitute the polar coordinate relationships

Replace yy with rsinθr \sin \theta and xx with rcosθr \cos \theta:

rsinθ=2rcosθ1r \sin \theta = 2r \cos \theta - 1

Step 3: Solve for rr

Rearranging the terms:

rsinθ2rcosθ=1r \sin \theta - 2r \cos \theta = -1

Factor out rr:

r(sinθ2cosθ)=1r (\sin \theta - 2 \cos \theta) = -1

Now solve for rr:

r=1sinθ2cosθr = \frac{-1}{\sin \theta - 2 \cos \theta}

Thus, the polar form of the equation y=2x1y = 2x - 1 is:

r=1sinθ2cosθr = \frac{-1}{\sin \theta - 2 \cos \theta}


Would you like more details about this transformation or any specific part of the process?

Here are 5 related questions that can deepen your understanding:

  1. How do you convert other linear equations from Cartesian to polar form?
  2. What is the geometrical interpretation of the polar form of a line?
  3. Can you convert nonlinear Cartesian equations into polar form?
  4. How would this equation change if the slope in the original Cartesian equation was different?
  5. What happens to the polar form if the constant term in the Cartesian equation changes?

Tip: When converting Cartesian equations into polar form, always remember that rr represents the distance from the origin to a point, and θ\theta is the angle from the positive xx-axis.

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Math Problem Analysis

Mathematical Concepts

Algebra
Polar Coordinates
Cartesian Coordinates

Formulas

x = r * cos(θ)
y = r * sin(θ)

Theorems

Polar to Cartesian Conversion

Suitable Grade Level

Grades 10-12