Math Problem Statement

(d) Find the polar coordinates of the points with Cartesian coordinates (3x, −3y). r = 14.4

Correct: Your answer is correct. cm 𝜃 = °

Solution

To find the polar coordinates of a point given in Cartesian coordinates (x,y)(x, y), the formulas are:

  1. r=x2+y2r = \sqrt{x^2 + y^2} (distance from the origin)
  2. θ=tan1(yx)\theta = \tan^{-1}\left(\frac{y}{x}\right) (angle in radians or degrees)

Here, the given Cartesian coordinates are (3x,3y)(3x, -3y). Using the formulas:

Step 1: Find rr

r=(3x)2+(3y)2=9x2+9y2=9(x2+y2)=3x2+y2r = \sqrt{(3x)^2 + (-3y)^2} = \sqrt{9x^2 + 9y^2} = \sqrt{9(x^2 + y^2)} = 3\sqrt{x^2 + y^2}

Since rr is provided as 14.414.4, we know: 3x2+y2=14.4    x2+y2=4.83\sqrt{x^2 + y^2} = 14.4 \implies \sqrt{x^2 + y^2} = 4.8

Step 2: Find θ\theta

θ=tan1(3y3x)=tan1(yx)\theta = \tan^{-1}\left(\frac{-3y}{3x}\right) = \tan^{-1}\left(\frac{-y}{x}\right)

The quadrant will determine the angle:

  • Since 3x>03x > 0 and 3y<0-3y < 0, the point lies in Quadrant IV, where the angle is measured as: θ=360tan1(yx)\theta = 360^\circ - |\tan^{-1}(\frac{y}{x})|

Let me know the specific values of xx and yy if you need further numerical calculations or have additional data!


Questions to Expand Learning:

  1. What is the significance of polar coordinates in real-world applications?
  2. Can Cartesian coordinates always be converted into polar coordinates?
  3. How does the quadrant of a point affect the angle θ\theta in polar coordinates?
  4. What are the potential uses of polar coordinates in engineering or physics?
  5. How do you interpret negative angles in polar coordinates?

Tip:

When converting Cartesian to polar coordinates, always check the quadrant of the point to adjust the angle θ\theta appropriately.

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Math Problem Analysis

Mathematical Concepts

Polar Coordinates
Trigonometry
Cartesian Coordinate System

Formulas

r = √(x² + y²)
θ = tan⁻¹(y/x)

Theorems

Pythagorean Theorem
Inverse Tangent Function Properties

Suitable Grade Level

Grades 10-12