Math Problem Statement

now with this understanding, solve: Find polar coordinates to represent (2,23)(2,23​)​ with r≥0r≥0​ and 0≤θ<2π0≤θ<2π​​. ​ Find polar coordinates to represent (2,23)(2,23​)​ with r≤0r≤0​ and 0≤θ<2π0≤θ<2π​.

Solution

Let's find the polar coordinates for the point (2,23)(2, 23) under both conditions: r0r \geq 0 and r0r \leq 0.

Part 1: Polar coordinates with r0r \geq 0

Polar coordinates are represented as (r,θ)(r, \theta), where:

  • rr is the radial distance from the origin to the point,
  • θ\theta is the angle from the positive xx-axis to the line connecting the origin to the point.

Given the Cartesian coordinates (x,y)=(2,23)(x, y) = (2, 23), the formulas to convert to polar coordinates are: r=x2+y2r = \sqrt{x^2 + y^2} θ=tan1(yx)\theta = \tan^{-1}\left(\frac{y}{x}\right)

  1. Compute rr: r=22+232=4+529=53323.086r = \sqrt{2^2 + 23^2} = \sqrt{4 + 529} = \sqrt{533} \approx 23.086

  2. Compute θ\theta: θ=tan1(232)tan1(11.5)1.740radians\theta = \tan^{-1}\left(\frac{23}{2}\right) \approx \tan^{-1}(11.5) \approx 1.740 \, \text{radians} Since the point is in the first quadrant, θ\theta remains 1.7401.740 radians.

Thus, the polar coordinates are approximately: (r,θ)(23.086,1.740)(r, \theta) \approx (23.086, 1.740)

Part 2: Polar coordinates with r0r \leq 0

For r0r \leq 0, the radial distance will be negative. In this case, we first compute the positive radial distance (which is still 23.08623.086) but then use a negative value for rr. To adjust for the negative rr, we must add π\pi to θ\theta (since this corresponds to pointing in the opposite direction).

r23.086r \approx -23.086 θ=1.740+π1.740+3.142=4.882radians\theta = 1.740 + \pi \approx 1.740 + 3.142 = 4.882 \, \text{radians}

Thus, the polar coordinates with r0r \leq 0 are approximately: (r,θ)(23.086,4.882)(r, \theta) \approx (-23.086, 4.882)

Final Results:

  1. With r0r \geq 0: (23.086,1.740)(23.086, 1.740)
  2. With r0r \leq 0: (23.086,4.882)(-23.086, 4.882)

Would you like more details or clarifications?

Here are 5 related questions for practice:

  1. What are the polar coordinates of (5,12)(5, 12)?
  2. How do you convert polar coordinates back to Cartesian form?
  3. What is the effect of changing the sign of rr in polar coordinates?
  4. How do you handle θ\theta when the point is in different quadrants?
  5. How do polar and Cartesian coordinates relate to trigonometric functions?

Tip: When converting Cartesian to polar coordinates, always ensure θ\theta is within the correct range [0,2π)[0, 2\pi), especially when dealing with different quadrants!

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Math Problem Analysis

Mathematical Concepts

Polar Coordinates
Cartesian Coordinates
Trigonometry

Formulas

r = sqrt(x^2 + y^2)
θ = tan^(-1)(y/x)

Theorems

Pythagorean Theorem
Inverse Trigonometric Functions

Suitable Grade Level

Grades 9-12