Skip to main content
Ch. 7 - Conic Sections
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Non è quello che usi tu?Cambia libro di testo
Capitolo 8, Problema 89

The equation of the red ellipse in the figure shown is x^2/25 + y^2/9 =1Write the equation for each circle shown in the figure.
Graph showing a red ellipse and three circles in a coordinate plane.

Guida verificata passo dopo passo
1
Identify the center of each circle. Since all circles are centered at the origin (0,0), their equations will be of the form x^2 + y^2 = r2, where r is the radius.
Determine the radius of each circle by observing where each circle intersects the x-axis or y-axis. The radius is the distance from the center to these points.
For the green circle, note the intersection points on the axes and use the distance from the origin to these points as the radius.
For the blue circle, similarly find the radius by measuring the distance from the origin to the points where the circle crosses the axes.
For the brown circle, find the radius by identifying the farthest points on the axes and use that distance as the radius to write the equation.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
8m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Equation of an Ellipse

An ellipse centered at the origin has the equation x²/a² + y²/b² = 1, where a and b are the lengths of the semi-major and semi-minor axes. The given ellipse has a = 5 and b = 3, indicating its horizontal and vertical stretches. Understanding this form helps distinguish ellipses from circles.
Video consigliato:
5:30
Foci and Vertices of an Ellipse

Equation of a Circle

A circle centered at the origin has the equation x² + y² = r², where r is the radius. Each circle in the figure can be described by identifying its radius from the graph and substituting it into this formula. Recognizing this standard form is essential for writing the equations of the circles.
Video consigliato:
5:18
Circles in Standard Form

Graph Interpretation and Radius Measurement

Interpreting the graph involves identifying the radius of each circle by measuring the distance from the center (origin) to any point on the circle along the x or y axis. This measurement is crucial to formulating the correct equation for each circle, as the radius directly determines the equation's constant term.
Video consigliato:
02:16
Graphs and Coordinates - Example