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Nonlinear Equations

Your nonlinearity confuses me

ax

5 

bx

4 

cx

3 tanh( 

x

)

dx

 2

x

ex

f

 0

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“The problem of not knowing what we missed is that we believe we haven't missed anything” –

Stephen Chew on Multitasking

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Example – General Engineering You are working for ‘DOWN THE TOILET COMPANY’ that makes floats for ABC commodes. The floating ball has a specific gravity of 0.6 and has a radius of 5.5 cm. You are asked to find the depth to which the ball is submerged when floating in water.

x

3  0 .

165

x

2  3 .

993  10  4  0

Figure:

Diagram of the floating ball

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For the trunnion-hub problem discussed on first day of class where we were seeking contraction of 0.015”, did the trunnion shrink enough when dipped in dry-ice/alcohol mixture?

1. Yes 2. No

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1.

2.

Example – Mechanical Engineering

Since the answer was a resounding NO, a logical question to ask would be: If the temperature of -108 o F is not enough for the contraction, what is?

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Finding The Temperature of the Fluid 

D

T

a

D

= 80 

T c T a

o  (

T

F

T

c = ???

o F )

dT D

= 12.363" ∆

D = -

0.015" 5 4.5

4 3.5

3 2.5

7 6.5

6 5.5

2 -350 -300 -250 -200 -150 T -100 -50 0 50 100   6 .

033  0 .

009696

T

 0 .

015  5 .

992  10  8

T c

2  7 .

457  10  5

T c

 6 .

349  10  3

f

(

T c

)  5 .

992  10  8

T c

2  7 .

457  10  5

T c

 8 .

651  10  3  0

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Finding The Temperature of the Fluid 

D

D T a

T c

 (

T

)

dT T

a = 80 o F

T

c = ???

o F

D

= 12.363" ∆

D = -

0.015"    1 .

228  10  5

T

2  6 .

195  10  3

T

 6 .

015  0 .

015   5 .

059  10  9

T c

3  3 .

829  10  6

T c

2  7 .

435  10  5

T c

 6 .

166  10  3

f

(

T c

)   5 .

059  10  9

T c

3  3 .

829  10  6

T c

2  7 .

435  10  5

T c

 8 .

834  10  3  0

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Nonlinear Equations

(Background) http://nm.mathforcollege.com

How many roots can a nonlinear equation have?

3 2 1 0 -1 -2 -3 -20 -10 sin(x)=2 has no roots 0 10 20

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How many roots can a nonlinear equation have?

sin(x)=0.75 has infinite roots 3 2 1 0 -1 -2 -3 -20 -10 0 10 20

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How many roots can a nonlinear equation have?

sin(x)=x has one root 3 2 1 0 -1 -2 -3 -20 -10 0 10 20

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How many roots can a nonlinear equation have?

3 0 -1 2 1 -2 -3 -20 sin(x)=x/2 has finite number of roots -10 0 10 20

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The value of

x

that satisfies

f

(

x

)=0 is called the A.

B.

C.

D.

root of equation

f

(

x

)

=0

root of function

f

(

x

) zero of equation

f

(

x

)

=0

none of the above

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1.

2.

3.

4.

A quadratic equation has ______ root(s) A. one B. two C. three D. cannot be determined

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1.

2.

3.

4.

For a certain cubic equation, at least one of the roots is known to be a complex root. The total number of complex roots the cubic equation has is

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A. one B. two C. three D. cannot be determined

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1.

2.

3.

4.

Equation such as

tan

(

x

)

=x

has __ root(s) 1.

2.

3.

4.

zero one two infinite

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1.

2.

3.

4.

A polynomial of order

n

has

1. n

-1 2.

n

3.

4.

n n

+1 +2 zeros

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1.

2.

3.

4.

The velocity of a body is given by

v

(

t

)

=

5

e

-

t

+4 , where

t

is in seconds and

v

is in m/s. The velocity of the body is

6

m/s at

t

=___.

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A. 0.1823 s B. 0.3979 s C. 0.9162 s D. 1.609 s

A.

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B.

C.

D.

END http://nm.mathforcollege.com

Newton Raphson Method

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This is what you have been saying about your TI-30Xa A. I don't care what people say The rush is worth the price I pay I get so high when you're with me But crash and crave you when you are away B. Give me back now my TI89 Before I start to drink and whine TI30Xa calculators you make me cry Incarnation of of Jason will you ever die C. TI30Xa – you make me forget the high maintenance TI89.

D. I never thought I will fall in love again!

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25% A.

25% 25% 25% B.

C.

D.

Newton-Raphson method of finding roots of nonlinear equations falls under the category of __________ method.

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A. bracketing B. open C. random D. graphical

1.

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2.

3.

4.

The next iterative value of the root of the equation

x

2 =4 using Newton-Raphson method, if the initial guess is 3 is

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A.

B.

C.

D.

1.500

2.066

2.166

3.000

1.

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2.

3.

4.

The root of equation

f

(x)=0 is found by using Newton-Raphson method. The initial estimate of the root is

x

o =3,

f

(3)=5. The angle the tangent to the function

f

(x) makes at

x

=3 is 57 o . The next estimate of the root,

x

1 most nearly is A. -3.2470

B.

C.

D.

-0.2470

3.2470

6.2470

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2.

3.

4.

The Newton-Raphson method formula for finding the square root of a real number

R

the equation

x

2

-R

=0 is,

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from

25%

A.

x i

 1 

x i

2 B.

C.

D.

x i

 1  3

x i

2

x i

 1  1 2  

x i

R x i

 

x i

 1  1 2   3

x i

R x i

 

1.

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2.

3.

4.

END http://nm.mathforcollege.com

Bisection Method

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Bisection method of finding roots of nonlinear equations falls under the category of a (an) method.

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A. open B. bracketing C. random D. graphical

1.

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2.

3.

4.

If for a real continuous function

f(x)

,

f

(

a

)

f

(

b

)<0, then in the range [

a,b

] for

f

(

x

)=0, there is (are)

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A.

B.

C.

D.

one root undeterminable number of roots no root at least one root

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1.

2.

3.

4.

The velocity of a body is given by

v

(

t

)

=5e -t +4

, where

t

is in seconds and

v

is in m/s. We want to find the time when the velocity of the body is 6 m/s. The equation form needed for bisection and Newton-Raphson methods is

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A.

B.

C.

D.

f (t)= 5e -t +4=0 f (t)= 5e -t +4=6 f (t)= 5e -t =2 f (t)= 5e -t -2=0

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1.

2.

3.

4.

To find the root of an equation

f

(

x

)

=0

, a student started using the bisection method with a valid bracket of [20,40]. The smallest range for the absolute true error at the end of the 2 nd iteration is

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A. 0 ≤ |E t |≤2.5

B. 0 ≤ |E t | ≤ 5 C. 0 ≤ |E t | ≤ 10 D. 0 ≤ |E t | ≤ 20

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1.

2.

3.

4.

For an equation like

x 2 =

0, a root exists at

x=

0. The bisection method cannot be adopted to solve this equation in spite of the root existing at

x

=0 because the function

f

(

x

)

=x

2

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A.

B.

C.

D.

is a polynomial has repeated zeros at

x

=0 is always non-negative slope is zero at

x

=0

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1.

2.

3.

4.

END http://numericalmethods.eng.usf.edu

How and Why?

Study Groups Help?

Studying Alone Studying with Peers

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I walk like a pimp – Jeremy Reed You know it's hard out here for a pimp, When he tryin to get this money for the rent, For the Cadillacs and gas money spent

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END http://nm.mathforcollege.com

Final Grade vs. First Test Grade

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A New Book on How Brain Works The Compass of Pleasure: How Our Brains Make Fatty Foods, Orgasm, Exercise, Marijuana, Generosity, Vodka, Learning, and Gambling Feel So Good

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