How do you find the f'(x) using the formal definition of a derivative if f(x)= 2x^2 - 3x+4f(x)=2x23x+4?

1 Answer
Apr 12, 2015

f'(x) = lim_(hrarr0) (f(x+h)-f(x))/h

For f(x) = 2x^2-3x+4
this becomes

f'(x)

= lim_(hrarr0)((2(x+h)^2 -3(x+h) +4) - (2x^2 -3x +4))/h

= lim_(hrarr0) (4xh + h^2-3h)/h

=lim_(hrarr0) (4x +h -3)

= 4x-3