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Lecture 3

# CMPSC 200 Lecture Notes - Lecture 3: Matlab, Square Root, Prime Number

3 pages27 viewsFall 2017

Department
Computer Science
Course Code
CMPSC 200
Professor
Lecture
3

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! Sottile
CMPSC 200 Programming for Engineers with MATLAB
Lecture 03 Outline
Related Reading: Chapter 2, §2.3.2; Chapter 3, §3.1 through §3.4
Array Operations
1) MATLAB stores “arrays” of data as matrices
2) A few equivalent statements to write ! " # \$
% &
a. A = [1 2; 3 4]
b. A = [1,2; 3,4]
c. A = [1 2;
3 4]
d. A = [1,2;
3,4]
3) The 'th row and (th column of a matrix can be found as A(i,j).
4) Shortcut for creating a row of regularly spaced sets of numbers
a. Start at a, increment in steps of b until you get to c
b. a:b:c or [a:b:c](MATLAB accepts both notations; the first is preferred)
c. If no b is indicated, default is a:1:b
Built-in MATLAB Functions – Part I
1) Common Math Operations
a. Absolute value: abs(x)
b. Square root: sqrt(x) (compare it against x^0.5)
c. )th root: nthroot(x,n)
d. Sign or Signum Function : sign(x), which returns:
i. 1 if the corresponding element of x is greater than zero
ii. 0 if the corresponding element of x equals zero
iii. -1 if the corresponding element of x is less than zero
e. Remainder: rem(x,y) (remainder of * divided by +)
f. Powers
i. Exponents: , - #./0 calculated as 5*10^10, 5*(10^10) or as 5E10
ii. Exponential: exp(x) calculates 12
g. Logarithms
i. 3456*7: log(x) (tricky to remember – many languages do this, though)
ii. 389/06*7: log10(x)
iii. Change of base formula to get others: 389;6*7 " <=>?2
<=>?;
2) Rounding functions
a. Rounding: round(x) (default, to integers; see help documentation for options)
b. Truncation: fix(x)
c. Floor (rounds to nearest integer towards @A): floor(x)
d. Ceiling (rounds to nearest integer towards A): ceil(x)