2What You Will Learn:How to find the derivatives and antiderivatives of polynomial functions.
3Derivatives and Antiderivatives Imagine you wanted to solve the following problem:- Suppose a ball is dropped from the upper observation deck of the CN Tower, 450 meters above the ground.a. What is the velocity of the ball after 5 seconds?b. How fast is the ball traveling when it hits the ground?We’ll come back to this.
4Remember Our Old Friend Slope? Slope of this lineOr:(x+h, f(x+h))What will happen as “h” gets closer to zero?(x, f(x))h
5The Derivative So…the formal definition of a derivative: This gives us the slope of a line tangent to a point on the curve. Another way to say this would be the rate of change of the function at that particular point.
6DifferentiationThe process of finding the derivative is called differentiation.Notation for f’(x) looks like: and is read “dy, dx”
7ExampleFind an expression for the slope of the tangent line to the graph of y = x2 – 4x + 2 at any point. In other words, findStep 1: find f(x+h):Step 2: find:Step 3: find:
8Example (continued)Using the derivative of the function we just found, find the slopes of the tangent line when x = 0 and x = 3.
9You TryFind an expression for the slope of the tangent line to the graph of y = 2x2 – 3x + 4 at any point (find ).Find the slopes of the tangent lines when x = -1 and x = 5.
10Rules for Finding Derivatives of Polynomials Constant Rule: The derivative of a constant function is 0. If f(x) = c then f’(x) = 0Power Rule: If f(x) = xn, where n is a rational number, then f’(x) = nxn-1.Constant Multiple of a Power Rule:If f(x) = cxn, where c is a constant and n is a rational number, then f’(x) = cnxn-1.Sum and Difference Rule: If f(x) = g(x) + h(x), then f’(x) = g’(x) + h’(x).
11Examples Find the derivative of the following: 1. f(x) = x6 2. f(x) = x2 – 4x + 23. f(x) = 2x4 – 7x3 + 12x2 – 8x – 10
13You Try Find the derivative of each function. 1. f(x) = x f(x) = x6 – x5 – x42. f(x) = x3 + 2x f(x)=(x + 1)(x2 – 2)3. f(x) = 2x5 – x + 5
14AntiderivativesWe can work “backwards” from a derivative back to a function. Very helpful for moving from velocity or rate of change back to the original function.Example. Find the antideriviative of the function f’(x) = 2x.We know it is x2 but what about x2 + 1, x2 + 2, x2 + 3…
15RulesPower Rule: If f(x) = xn, where n is a rational number other than -1, the antiderivative is:Constant Multiple of a Power Rule: If f(x) = kxn, where n is a rational number other than -1 and k is a constant, the antiderivative is:Sum and Difference Rule: If the antiderivatives of f(x) and g(x) are F(x) and G(x) respectively, then the antiderivative off(x) + or – g(x) is
16Examples Find the antiderivative of each function. 1. f(x) = 3x7 2. f(x) = 4x2 – 7x + 53. f(x) = x(x2 + 2)
17You Try Find the antiderivative of each function. 1. f(x) = 32x3 2. f(x) = 35x6 + 12x2 – 6x + 123. f(x) = x2(x2 + x + 3)
20SummaryDerivative of functions = rate of change of the function. Measures how fast a function changes.Antiderivative of functions = if you are given an rate of change, you can work your way back to the original function (less c). If you are given a point from the original function, you can even “recover” a value for c.