Derivatives Polynomial
\[f(X)=\frac{ 2x^2+3x+2 }{ Sqrtx }\] f'(x)=
Use the quotient rule. \[\left( \frac{ f }{ g} \right)\prime=\frac{ f \prime g-g \prime f }{ g ^{2}}\]
whre is g(x) in the question?
\[f(x)=2x ^{2}+3x+2 \] and \[g(x)=\sqrt{x}\] or if you prefer, you can just divide the \[x ^{1/2}\] into the numerator and you are left with a simple polynomial in x that can be differentiated term by term.
Oh I see. So g(x)=sqrt(x)!
You should get the same result either way, but if we divide, your polynomial becomes\[2x ^{3/2}+3x ^{1/2}+2x ^{-1/2}\] So, then you can just take the derivative of each term by the power rule. Bring the power down and raise the function to one power less.
I am confused!
what is the first step?
If you have x^n, Then \[\frac{ d }{ dx }x ^{n}=nx ^{n-1}\] So look at your first term. What is it? It is 2x^(3/2), so the rules says to bring the power down, and raise it to one power less.
Now just apply that same rule to each of the three terms.
d/dx2(x^2)+d/dx3(x)+d/dx(2)
That would be the case if you didn't have that square root on the bottom, but since you do, I believe you should use the one I typed for you after we divided by square root of x.
what is the next actually process?
I know the fact that I have to bring numbers in front of x ? :/
Yep, for each term with an x in it, in order to find its derivative, you have to bring the power down and raise the power to one power less
so 3/2*2?
Yes, the constants in front of each x term just get multiplied by whatever power you bring down.
ok, so it is 6/2?
Yes, then that reduces to 3.
OH! thats really cool. i got it!
So, can I see your final answer to the derivative?
Ok, hold on im caculating
ok, is it 3x+3/2x+(-x)?
You forgot about the part where the exponent gets reduced by 1 power less.
Ok i will redo it again,
k
\[f(x)+3x ^{-1/2}+3/2x ^{1/2}+x ^{1/2}\]
is this right? @calmat01
@Dodo1 Almost. You need to substract 1 from the power of 2x^(-1/2) and bring down the power first. so the last term should be -x^(-3/2)
And the second term should have a negative in the exponent. It should be (3/2)x^(-1/2)
Join our real-time social learning platform and learn together with your friends!