I don't know how to do this but I'd like to learn how:
A question is "Given that 2x² - 5x + 3, find dy/dx from first principles."
Can anyone please help me
Hmmmm....
dy/dx = 4x - 5 ?
To learn how to differentiate polynomials.
http://en.wikipedia.org/wiki/Calculus_with_polynomials
Write out the difference quotient for $\displaystyle f(x)=2x^2-5x+3$:
$\displaystyle
DQ(f,h)=\frac{f(x+h)-f(x)}{h}=\frac{2(x+h)^2-5(x+h)+3-2x^2+5x-3}{h}
$
.............. $\displaystyle = \frac{4hx+2h^2-5h}{h}=4x-5+2h$
So:
$\displaystyle
\frac{df}{dx}=\lim_{h \to 0} DQ(f,h)=4x-5
$
CB