Practice Final Exam - Numerical Analysis | MATH 128A, Exams of Mathematical Methods for Numerical Analysis and Optimization

Material Type: Exam; Class: Numerical Analysis; Subject: Mathematics; University: University of California - Berkeley; Term: Spring 2009;

Typology: Exams

Pre 2010

Uploaded on 10/01/2009

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UCB Math 128A, Spring 2009: Final Exam
May 16, 2009
Name:
SID:
GSI:
No books, no notes, no calculators
Justify all answers
Do all of the 6 problems
Exam time 3 hours
Grading
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Download Practice Final Exam - Numerical Analysis | MATH 128A and more Exams Mathematical Methods for Numerical Analysis and Optimization in PDF only on Docsity!

UCB Math 128A, Spring 2009: Final Exam

May 16, 2009

Name:

SID:

GSI:

  • No books, no notes, no calculators
  • Justify all answers
  • Do all of the 6 problems
  • Exam time 3 hours

Grading

(a) Given a > 0, what (positive number) is the following iteration in-

tended to compute?

pn+1 =

p

3 n + 3apn

3 p^2 n + a

(b) Assuming that the sequence {pn}

∞ n=0 converges, find the order of

convergence.

Find the total number of floating point operations (Additions + Sub-

tractions + Multiplications + Divisions) for the following computations:

(a) λ = x

t Ax where A is an n × n matrix and x is an n × 1 vector.

(b) The matrix product C = AB where A is n × m and B is m × p.

(c) Backward substitution using the following MATLAB code:

x=b;

for i=n:-1:

for j=i+1:n

x(i)=x(i)-A(i,j)*x(j);

end

x(i)=x(i)/A(i,i);

end

(a) Derive the difference formula for f

′′ (x 0 ) with error term:

f

′′ (x 0 ) =

f (x 0 + h) − 2 f (x 0 ) + f (x 0 − h)

h^2

h

2

f

(4) (ξ), ξ ∈ [x 0 − h, x 0 + h].

(b) Suppose each evaluation of f gives a round-off error bounded by ε,

and that |f

(4) (x)| ≤ M. Calculate the optimal h which minimizes

the error in the computed f

′′ (x 0 ).

(a) Find a numerical integration rule of the form

− 2

f (x) dx = af (0) + bf (−1) + cf (−2)

which is exact for polynomials of the highest possible degree.

(b) Use the result of (a) to design a scheme for the IVP y

′ = f (t, y),

y(0) = y 0 of the form:

wi+1 = wi− 2 + αf (ti, wi) + βf (ti− 1 , wi− 1 ) + γf (ti− 2 , wi− 2 )

(c) Evaluate the local truncation error τ using Taylor expansions, and

find the best possible m such that τ = O(h

m ).

(d) Determine if the scheme is strongly stable, weakly stable, or unstable.