/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 77 The midpoint formula in polar co... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

The midpoint formula in polar coordinates: \(M=\left(\frac{r \cos \alpha+R \cos \beta}{2}, \frac{r \sin \alpha+R \sin \beta}{2}\right)\) The midpoint of a line segment connecting the points \((r, \alpha)\) and \((R, \beta)\) in polar coordinates can be found using the formula shown. Find the midpoint of the line segment between \((r, \alpha)=\left(6,45^{\circ}\right)\) and \((R, \beta)=\left(8,30^{\circ}\right),\) then convert these points to rectangular coordinates and find the midpoint using the "standard" formula. Do the results match?

Short Answer

Expert verified
Yes, the midpoints match when calculated from both polar and rectangular coordinates.

Step by step solution

01

Convert Angles from Degrees to Radians

To use trigonometric functions, we need angles in radians. Convert \(45^{\circ}\) to radians: \( \alpha = \frac{45\pi}{180} = \frac{\pi}{4} \). Likewise, convert \(30^{\circ}\) to radians: \( \beta = \frac{30\pi}{180} = \frac{\pi}{6} \).
02

Calculate Rectangular Coordinates of Each Point

Use the conversion formulas: \( x = r \cos\alpha \) and \( y = r \sin\alpha \). For \((r, \alpha) = (6, \frac{\pi}{4})\), we have \( x_1 = 6 \cos \frac{\pi}{4} = 3\sqrt{2} \) and \( y_1 = 6 \sin \frac{\pi}{4} = 3\sqrt{2} \). For \((R, \beta) = (8, \frac{\pi}{6})\), \( x_2 = 8 \cos \frac{\pi}{6} = 4\sqrt{3} \) and \( y_2 = 8 \sin \frac{\pi}{6} = 4 \).
03

Find Midpoint in Polar Coordinates

Using the polar midpoint formula, calculate: \[ M_x = \frac{6 \cos \frac{\pi}{4} + 8 \cos \frac{\pi}{6}}{2} = \frac{3\sqrt{2} + 4\sqrt{3}}{2} \] and \[ M_y = \frac{6 \sin \frac{\pi}{4} + 8 \sin \frac{\pi}{6}}{2} = \frac{3\sqrt{2} + 4}{2}. \]
04

Find Midpoint in Rectangular Coordinates

Compute midpoint using \((x_1, y_1)\) and \((x_2, y_2)\): \[ M'_x = \frac{x_1 + x_2}{2} = \frac{3\sqrt{2} + 4\sqrt{3}}{2} \] and \[ M'_y = \frac{y_1 + y_2}{2} = \frac{3\sqrt{2} + 4}{2}. \]
05

Compare Both Midpoints

The midpoint calculated using polar coordinates \((M_x, M_y)\) matches the midpoint using rectangular coordinates \((M'_x, M'_y)\). Thus, the results indeed match.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Polar Coordinates
Polar coordinates are a way of representing points in a plane using two values: a radial distance from a reference point (often called the origin) and an angle from a reference direction (usually the positive x-axis in a standard Cartesian coordinate system). This system offers an alternative to rectangular coordinates, which use x and y to specify a location on a plane.

Unlike the Cartesian system, polar coordinates emphasize rotation and angle, which makes them particularly useful in scenarios involving circular and spiral paths, as well as oscillatory motion. Polar coordinates are denoted as \(r, \theta\), where \theta\ is the angle and \(r\) is the distance from the origin.

This system is especially handy in fields like physics, robotics, and engineering when dealing with problems involving rotation and radial symmetry.
Rectangular Coordinates
Rectangular coordinates, also known as Cartesian coordinates, represent points in a plane based on their horizontal and vertical distances from a pair of axes that intersect at the origin. This system is foundational in geometry, algebra, and calculus, allowing us to plot equations as visual graphs and find intersections of lines, curves, and planes.

Each point on the plane can be expressed as \(x, y\), where \(x\) represents the horizontal distance and \(y\) the vertical distance. The ease of visualizing straight lines is central to the usefulness of rectangular coordinates, particularly in everyday contexts and linear problem-solving.

Despite their differences, converting between polar and rectangular coordinates is an important skill, helping to bridge problems in various mathematical contexts.
Trigonometric Functions
Trigonometric functions are foundational mathematical tools that relate angles of a triangle to the lengths of its sides. They are especially pivotal when dealing with polar coordinates. The primary functions—sine, cosine, and tangent—are frequently utilized to switch between polar and rectangular coordinates.

In polar coordinates, the sine and cosine functions help illustrate the relationship between the angle \(\theta\) and the x and y values of the corresponding rectangular coordinates. Specifically, \(x = r \cos(\theta)\) and \(y = r \sin(\theta)\), where \(r\) is the radial distance and \(\theta\) the polar angle. These relationships enable the seamless transformation from one coordinate system to another, a crucial skill in advanced mathematics applications.
Angle Conversion
Angle conversion involves changing the units or representation of angles, often from degrees to radians or vice versa. This process is important because many mathematical functions and applications, especially trigonometric ones, require angle measurements in radians.

To convert degrees to radians, multiply the number of degrees by \(\frac{\pi}{180}\). For example, converting \(45^\circ\) to radians results in \(\frac{\pi}{4}\). Similarly, \(30^\circ\) in radians is \(\frac{\pi}{6}\).

This conversion makes it possible to use angles in computations involving trigonometric functions, helping us solve problems more efficiently, such as finding a midpoint in different coordinate systems, exemplified in the calculations of our exercise.
Coordinate Transformation
Coordinate transformation denotes the process of converting coordinates from one form to another, such as from polar to rectangular. This is achieved using trigonometric functions, as seen in \(x = r \cos(\theta)\) and \(y = r \sin(\theta)\). These transformations make it easier to apply standard geometric formulae, like those for midpoints or distances, to problems presented in polar form.

Such transformations are not limited to mathematical abstractions but are vital in practical applications—graphics, navigation, and physics, where interpreting and manipulating different coordinate forms are necessary.

The exercise we reviewed involves converting polar coordinates to rectangular to verify midpoint calculations, demonstrating the practical relevance of these transformations in ensuring accurate problem-solving and analysis across varied contexts.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The Perpendicular Distance from a Point to a Line: \(d=\left|\frac{A x_{1}+B y_{1}+C}{\sqrt{A^{2}+B^{2}}}\right|\) The perpendicular distance from a point \(\left(x_{1}, y_{1}\right)\) to a given line can be found using the formula shown, where \(A x+B y+C=0\) is the equation of the line in standard form \((A, B, \text { and } C\) are integers). Use the formula to verify that \(P(-6,2)\) and \(Q(6,4)\) are an equal distance from the line \(y=-\frac{1}{2} x+3\) .

Find the vertex, focus, and directrix for the parabolas defined by the equations given, then use this information to sketch a complete graph (illustrate and name these features). For Exercises 43 to 60 , also include the focal chord. $$y^{2}=20 x$$

Planetary motion: The perihelion, aphelion, and orbital period of the planets Jupiter, Saturn, Uranus, and Neptune are shown in the table. Use the information to answer or complete the following exercises. The formula $$L=2 \pi \sqrt{0.5\left(a^{2}+b^{2}\right)}$$ can be used to estimate the length of the orbital path. Recall for an cllipse, \(c^{2}=a^{2}-b^{2}\). $$\begin{array}{|l|c|c|c|} \hline \text { Planet } & \begin{array}{c} \text { Perihelion } \\ \left(10^{6} \mathrm{mi}\right) \end{array} & \begin{array}{c} \text { Aphelion } \\ \left(10^{6} \mathrm{mi}\right) \end{array} & \begin{array}{c} \text { Period } \\ (y r) \end{array} \\ \hline \text { Jupiter } & 460 & 507 & 11.9 \\ \hline \text { Saturn } & 840 & 941 & 29.5 \\ \hline \text { Uranus } & 1703 & 1866 & 84 \\ \hline \text { Neptune } & 2762 & 2824 & 164.8 \\ \hline \end{array}$$ Find the eccentricity of the planets Jupiter and Saturn.

Fill in the blank with the appropriate word or phrase. Carefully reread the section if needed. For an ellipse, the relationship between \(a, b,\) and \(c\) is given by the foci equation______since \(c

Find the equation of an ellipse (in standard form) that satisfies the following conditions: vertices at (-6,0) and (6,0)\(;\) foci at (-4,0) and (4,0)

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.