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Lec-10 Manipulations of Matlab Matrices. Built-in functions. The chapter will be covered quickly There are quite a few built-in functions in MATLAB If you can think of it, it is probably available To find documentation, use Google to find documentation: e.g. google “sine matlab”
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Built-in functions • The chapter will be covered quickly • There are quite a few built-in functions in MATLAB • If you can think of it, it is probably available • To find documentation, use Google to find documentation: e.g. google “sine matlab” google “standard deviation matlab”
Nesting of functions • Just in regular math where one can use f(g(x)) • Arguments can be scalars, vectors or matrices
Parameters (Arguments) Parameter and argument are almost synonyms sqrt(x) is a function with one parameter If we call sqrt as sqrt(4) 4 is the argument passed to the parameter sin(x) is a function of one parameter too If we call it as sin(sqrt(4)) It’s the value of sqrt(4) is passed as the argument to its one parameter.
Functions with multiple arguments • We have encountered linspace(1,10,100) • rand(3,4) • rem(12.1,5.0) ans= 2.1
Matlab help • You can use MATLAB help • If you don’t know the name, use Google. • Try “help” tab in MATLAB window.
Trigonometric Functions • sin(x) sine of x expressed in radians) • cos(x), tan(x) • sind(x) sine of x in degrees • cosd(x) • tand(x) etc.
Data Analysis Functions • max (maximum) • min (minimum) • mean (average) • median • sum (sum total of elements) • prod (product) • sort (sort elements) • cumsum, cumprod (cummulative sum, prod)
Try • Try out at least 10 of the functions I just described with both scalar and vector inputs • At least one of fix, round, ceil • At least one of the trig functions in radians and degrees. • Some of the sum, prod, cumsum • Try log of exp • Try max with vector output • Compute the average location of the maximum values from the columns of the matrix magic(5) • Sort the rows of magic(5) according to the third column
Problem Problem 3.20: • Throw one die • Throw two dice • Throw two dice 100 times along with the total of each throw • Histogram the sum
Problem >> one=floor(rand(1)*6+1) one = 5 >> two=floor(rand(1,2)*6+1) two = 2 4 >> sim=floor(rand(2,10).*6+1) sim = 1 2 5 3 2 1 4 1 1 1 4 4 5 1 6 5 6 3 6 5 >> total=sum(sim) total = 5 6 10 4 8 6 10 4 7 6 >> hist(total);