Problem of the Day No calculator! What is the instantaneous rate of change at x = 2 of f(x) = x2 - 2...

13
Problem of the Day No calculator! What is the instantaneous rate of change at x = 2 of f(x) = x2 - 2 ? x - 1 A) -2 C) 1/2 E) 6 B) 1/6 D) 2

Transcript of Problem of the Day No calculator! What is the instantaneous rate of change at x = 2 of f(x) = x2 - 2...

Problem of the Day No calculator!

What is the instantaneous rate of change at x = 2 of f(x) = x2 - 2 ? x - 1

A) -2 C) 1/2 E) 6

B) 1/6 D) 2

Problem of the Day No calculator!

What is the instantaneous rate of change at x = 2 of f(x) = x2 - 2 ? x - 1

A) -2 C) 1/2 E) 6

B) 1/6 D) 2

(take derivative and then substitute in)

Newton's Method

A technique for approximating the real zeroes of a function using tangent lines

Newton's Method

A technique for approximating the real zeroes of a function using tangent lines

If the function is continuous on [a, b] and differentiable on (a, b) and if f(a) and f(b) differ in sign then by the ___________________________ f must have at least one zero in (a, b)

a b

y

x

Newton's Method

A technique for approximating the real zeroes of a function using tangent lines

If the function is continuous on [a, b] and differentiable on (a, b) and if f(a) and f(b) differ in sign then by the Intermediate Value Theorem f must have at least one zero in (a, b)

a b

y

x

Newton's Method

A technique for approximating the real zeroes of a function using tangent lines

Visual Calculus Link

Newton's Method

A technique for approximating the real zeroes of a function using tangent lines

In summary, the x-intercept will be approximately

xn+1 = xn - f(xn) f '(xn)

Calculate 3 iterations of Newton's Method to approximate a zero of f(x) = x2 - 2 starting with x = 1.

Iteration xn f(xn) f '(xn)

f(xn)f '(xn)

xn - f(xn)f '(xn)

Calculate 3 iterations of Newton's Method to approximate a zero of f(x) = x2 - 2 starting with x = 1.

Iteration xn f(xn) f '(xn)

f(xn)f '(xn)

xn - f(xn)f '(xn)

123

11.51.416

-1.25.006945

232.83

-.5.083.002451

1.51.4161.414216

Calculate 3 iterations of Newton's Method to approximate a zero of f(x) = x2 - 2 starting with x = 1.

Iteration xnyour equation

nderiv(Y1,x,x)

x -

xn - f(xn)f '(xn)

Y1 =

Ti-84

Y2 =

Y3 =

Ti-Nspire

f1 = your equation

f2 =

f3 =

Newton's Method will not always produce an answer, such as when

1) the derivative within the interval is zero at any point2) functions similar to f(x) = x1/3

You can test for convergence to see if it will work with the following formula

f(x) f ''(x) [f '(x)]2 < 1

Another precaution

Do not round in intermediary steps. Let your calculator carry the numbers.