# Thread: three answers for a simple derivative

1. ## three answers for a simple derivative

Hi,
I just did an online test that had the question below. I have no Idea what it was asking. I know that y'= -2x. Although I was not sure why there was three answer boxes layed out like they where and I am even more confused with the answer they gave me at the end of the test.

Find derivative of y=−x^2+3.
y′=________ x^2 + __________ x+ ________________ .

Answer Key: 0, -2, 0 (numeric)

Can someone please Explain this to me?

2. ## Re: three answers for a simple derivative

Originally Posted by Kristy
Hi,
I just did an online test that had the question below. I have no Idea what it was asking. I know that y'= -2x. Although I was not sure why there was three answer boxes layed out like they where and I am even more confused with the answer they gave me at the end of the test.

Find derivative of y=−x^2+3.
y′=________ x^2 + __________ x+ ________________ .

Answer Key: 0, -2, 0 (numeric)

Can someone please Explain this to me?
wow. Maybe you should switch to a more difficult course or something.

What they have done is give you place holders for the coefficients of a quadratic polynomial.

As you noted $y'=-2x$ this is

$0\cdot x^2 + (-2)x+0$ hence your 3 coefficients (0,-2,0)

3. ## Re: three answers for a simple derivative

Oh, I see, Thanks so much for your very prompt answer.

4. ## Re: three answers for a simple derivative

Originally Posted by Kristy
Hi,
I just did an online test that had the question below. I have no Idea what it was asking. I know that y'= -2x. Although I was not sure why there was three answer boxes layed out like they where and I am even more confused with the answer they gave me at the end of the test.

Find derivative of y=−x^

Can someone please Explain this to me?
Romsek answered while I was fiddling