Math Problem Statement

Find the rectangular coordinates of the point with polar coordinates (4, -2π/3).

Solution

The problem is asking to find the rectangular coordinates (Cartesian coordinates) of the point given in polar coordinates (4,2π3)(4, -\frac{2\pi}{3}).

Conversion from Polar to Rectangular Coordinates:

The formulas to convert from polar to rectangular coordinates are: x=rcos(θ)x = r \cdot \cos(\theta) y=rsin(θ)y = r \cdot \sin(\theta) where rr is the radial distance and θ\theta is the angle in radians.

Given:

  • r=4r = 4
  • θ=2π3\theta = -\frac{2\pi}{3}

1. Calculating xx:

x=4cos(2π3)x = 4 \cdot \cos\left(-\frac{2\pi}{3}\right) Since cos(2π3)=cos(2π3)=12\cos\left(-\frac{2\pi}{3}\right) = \cos\left(\frac{2\pi}{3}\right) = -\frac{1}{2}, we have: x=4(12)=2x = 4 \cdot \left(-\frac{1}{2}\right) = -2

2. Calculating yy:

y=4sin(2π3)y = 4 \cdot \sin\left(-\frac{2\pi}{3}\right) Since sin(2π3)=sin(2π3)=32\sin\left(-\frac{2\pi}{3}\right) = -\sin\left(\frac{2\pi}{3}\right) = -\frac{\sqrt{3}}{2}, we have: y=4(32)=23y = 4 \cdot \left(-\frac{\sqrt{3}}{2}\right) = -2\sqrt{3}

Thus, the rectangular coordinates are: (2,23)\boxed{(-2, -2\sqrt{3})}

Would you like further details or have any questions?

Here are five related questions to explore:

  1. How can we convert rectangular coordinates to polar coordinates?
  2. What are the common values of sine and cosine for angles in radians?
  3. How can you interpret negative angles in polar coordinates geometrically?
  4. Can polar coordinates have negative radial values?
  5. What is the significance of the angle 2π3-\frac{2\pi}{3} in the unit circle?

Tip: When converting polar to rectangular coordinates, ensure the angle is in radians for trigonometric calculations unless otherwise specified.

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Math Problem Analysis

Mathematical Concepts

Polar Coordinates
Rectangular Coordinates
Trigonometry

Formulas

x = r * cos(θ)
y = r * sin(θ)

Theorems

Polar to Rectangular Coordinate Conversion

Suitable Grade Level

High School (Grades 9-12)