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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 17

Graph each ellipse and locate the foci. 7x² = 35-5y²

Guida verificata passo dopo passo
1
Rewrite the given equation to standard form of an ellipse. Start with the equation: \(7x^{2} = 35 - 5y^{2}\). Move all terms to one side to get \(7x^{2} + 5y^{2} = 35\).
Divide every term by 35 to normalize the equation: \(\frac{7x^{2}}{35} + \frac{5y^{2}}{35} = \frac{35}{35}\), which simplifies to \(\frac{x^{2}}{5} + \frac{y^{2}}{7} = 1\).
Identify the values of \(a^{2}\) and \(b^{2}\) from the standard form \(\frac{x^{2}}{a^{2}} + \frac{y^{2}}{b^{2}} = 1\). Here, \(a^{2} = 5\) and \(b^{2} = 7\). Since \(b^{2} > a^{2}\), the major axis is vertical.
Calculate the focal distance \(c\) using the formula \(c^{2} = b^{2} - a^{2}\). Substitute the values to get \(c^{2} = 7 - 5\).
Locate the foci on the graph along the major axis (the y-axis) at points \((0, \pm c)\). Then, sketch the ellipse centered at the origin with vertices at \((0, \pm \sqrt{7})\) and co-vertices at \((\pm \sqrt{5}, 0)\).

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Standard Form of an Ellipse

An ellipse can be expressed in the standard form as (x-h)²/a² + (y-k)²/b² = 1, where (h, k) is the center, and a and b are the lengths of the semi-major and semi-minor axes. Converting the given equation into this form is essential for graphing and identifying key features.
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