- Grading date for lab 2 is now Thursday, Feb 18
- How should frequencies of sine wave behave in vector lab?
- Stay constant as you increase range of x values because number of cycles generated increases exactly proportionally to that range
- …Until range gets so large that you have less than 2 samples per cycle and
Nyquist’s Theorem kicks in
- Sections 6.1 and 6.2
- Plot = show data in graph
- x and y axes assumed based on data until you change them
- Can title axes with
xlabel,ylabel - Lots of different functions for different kinds of graph, e.g.,
plot- central plotting functionplot( xvector, yvector )
plotyy
- Functions to customize graphs
- Examples
- Plot y =x2 over 1 ≤ x ≤ 10
>> % Plot y = x^2 >> % Algorithm: make vector of xs >> % make vector of ys >> % plot xs, ys >> xs = linspace( 1, 10 ); >> ys = xs .^ 2; >> plot( xs, ys ); >> axis square >> axis equal
- Order of growth (plot 2 functions in different colors)
- x vs ln x
- Tendency to think of ln x as roughly same size as x, just leveling off
- Reality for modestly large x values is that ln x might as well be 0
>> % Plot y = log x and y = x on same axes >> clf >> xs = linspace( 1, 1000, 1000 ); >> ys = log( xs ); >> hold off >> plot( xs, ys ); >> hold on >> plot( xs, xs, 'r' )
- Plot y =x2 over 1 ≤ x ≤ 10
- Handout
- Grade by February 25
- Jagged graphs may result from plotting over too few t values
>> % Jagged graph >> xs = linspace( 1, 10, 3 ); >> ys = xs .^ 2; >> clf >> plot( xs, ys )
- Parametric Equations
- Watch “Parametric Curves — Basic Graphing” video at https://www.youtube.com/watch?v=tsnHL1Lb5MU