Which of the following correctly identifies the vertices that lie on the major axis of the conic section shown below? (x-2)^2/4+(y+5)^2/9=1 A. (-5,5) and (-5,-1) B. (0,-5) and (4,-5) C. (5,5) and (-1,-5) D. (2,-2) and (2,-8)
HI!!!
do you know what conic section this is?
I think a hyperbola
nope
because it has a plus sign between the two terms, not a minus sign, it is not a hyperbola
Ohh okay
so what is it?
ellipse
right and what is the center of this ellipse?
Im not sure but I think 4
oh no the center is a point in the plane, an ordered pair \((h,k)\) not a number
your ellipse is written in standard form \[\frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1\] center is \((h,k)\)
(-2,5)
hmm close but no
would it be (2,-5)
\[\frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1\\ \frac{(x-2)^2}{4}+\frac{(y+5)^2}{9}=1\]
yes \((2,-5)\)
we need to know all these things to get the answer, i am not asking just to waste your time now we need to know two more things
|dw:1449514647833:dw|
the second one
yes, and now we are just about done
because we know the center is \((2,-5)\) and we know the major axis is vertical, so the first coordinates of both endpoints of the major axis will lie ABOVE and BELOW \((2,-5)\)
that means this |dw:1449514853430:dw|
we did not even have to find that they are 3 units above and below \((2,-5)\) because you only had one answer choice where the first coordinate was 2
I think it would be A based off of that
we could find the 3 if you like
A???
yes is that not right?
i will let you look at the answer choices and the answer i wrote above and figure out which one it is for yourself
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