Precalculus: Mathematics for Calculus, 7th Edition

Published by Brooks Cole
ISBN 10: 1305071751
ISBN 13: 978-1-30507-175-9

Chapter 11 - Review - Exercises - Page 833: 24

Answer

(a) Center: $C(1,-2)$ $V_1(1,-2-2\sqrt 2)$ and $V_2(1,-2+2\sqrt 2)$ $F_1(1,-4)$ and $F_2(1,0)$ (b) Length of the major axis: $2a=4\sqrt 2$ Length of the minor axis: $2b=4$ (c)

Work Step by Step

Equation of an ellipse with center at $(h,k)$ (major axis is vertical): $\frac{(x-h)^2}{b^2}+\frac{(y-k)^2}{a^2}=1$ $2x^2+y^2=2+4(x-y)$ $2x^2-4x+y^2+4y=2$ $2x^2-4x+2+y^2+4y+4=2+2+4$ $2(x-1)^2+(y+2)^2=8$ $\frac{(x-1)^2}{4}+\frac{(y+2)^2}{8}=1$ $\frac{(x-1)^2}{2^2}+\frac{[y-(-2)]^2}{(2\sqrt 2)^2}=1$ $h=1$ $k=-2$ Center: $C(1,-2)$ $a=2\sqrt 2$ $b=2$ $c^2=a^2-b^2=8-4=4$ $c=2$ The given equation can be obtained by shifting $\frac{x^2}{2^2}+\frac{y^2}{(2\sqrt 2)^2}=1$ right 1 unit and downward 2 units. In this equation: Vertices: $V(0,±a)$ $V_1(0,-2\sqrt 2)$ and $V_2(0,2\sqrt 2)$ Foci: $F(0,±c)$ $F_1(0,-2)$ and $F_2(0,2)$ Now, shift these points 1 unit to the right and 2 units downward: $V_1(1,-2-2\sqrt 2)$ and $V_2(1,-2+2\sqrt 2)$ $F_1(1,-4)$ and $F_2(1,0)$ Length of the major axis: $2a=4\sqrt 2$ Length of the minor axis: $2b=4$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.