Answer:
a. x² +4y² +4z² = 1
b. x² +4y² +z² = 1
Step-by-step explanation:
a. In "intercept form", the given equation can be written as ...
(x/1)² + (y/(1/2))² = 1
When the ellipse is revolved around the x-axis, the z-intercept will match the y-intercept, so the equation becomes ...
(x/1)² + (y/(1/2))² + (z/(1/2))² = 1
x² +4y² +4z² = 1
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b. Likewise, revolving the figure around the y-axis will make the z-intercept the same as the x-intercept. That equation is ...
x² + 4y² +z² = 1
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See the attachments. The first shows revolution about the x-axis; the second shows revolution about the y-axis.