Question

Find the derivative of the following from first principle:

a) f(x) = x-x^3

B) y = (2x-5)^2

Answer 1

if your looking for the derivative (y')

a. f(x) = x - x^3
= 1 - 3x^2

b. y = (2x - 5)^2
[using chain rule]
2(2x - 5) (2)
=4(2x - 5)

[not sure about "a" though ^^;;]

Answer 2

I tried using the rule but I keep getting the wrong answer through the method

Answer 3

This rule I meant : f(x+h)-f(x)/h

Answer 4

whats your attempt ?

Answer 5

k got it.