三种常用常用的调用方法：help命令、doc命令、look for命令。
一、help命令
调用格式为：‘help 函数名’，如调用正弦函数的意义和用法：输入‘help sin’。
二、doc命令
调用格式为：‘doc 函数名’，如调用正弦函数的意义和用法：输入‘doc sin’。
三、lookfor命令
如果要查找具有某种功能的命令或函数，但不知道确切名称时，可以通过完整的或部分的关键字来搜索相关内容。如图所示
>> lookfor draw
drawnow - Update figure windows and process callbacks
ribbon - Draw 2-D lines as ribbons in 3-D.
dee4plt - Draw a two mass, two spring system.
dee4plti - Initialize the draw_spring figure window.
featuresmap - draws the map with the features of a GenBank structure.
featureview - draws the map with the features of a GenBank structure.
rnaplot - draws RNA secondary structure
traceplot - draws a nucleotide trace plot.
customnodedraw - User function example to draw customized nodes.
commblktcmdec_drawicon - Draw icon for TCM decoder blocks.
loopstruct - Draws feedback loop configuration.
NDD_figs - Draws feedback loop
rlc_figs - Draws a parallel bandpass RLC circuit
pctdemo_taskfin_callback2_setup - Prepare a figure for drawing a graph.
drawgsmmask - Utility to draw a GSM mask for the DDC filter chain demo:
priv_drawrlsdemo - Draws the schematic block diagram for the RLS adaptive
emaxdrawdown - Compute expected maximum drawdown for a Brownian motion.
maxdrawdown - Calculate maximum drawdown for one or more price series.
draw_modsimrand_fig - Function to draw figure window for modsimrand function
drawSudoku - Function for drawing the Sudoku board
pdecirc - Draw circle, update Geometry Description matrix.
pdeellip - Draw ellipse, update Geometry Description matrix.
pdepoly - Draw polygon, update Geometry Description matrix.
pderect - Draw rectangle, update Geometry Description matrix.
drawacc - Script that draws the ACC Benchmark Schematic.
wheel - Draw a car wheel for the ACC Benchmark schematic.
drawmag - function [sysout,pts] = drawmag(in,init_pts)
drawpznumbers - Draw the PZNumbers
info2mask - (S) Draws a filter mask specified in the structure S
vrdrawnow - Flush pending virtual reality scene events.
gline - Draw a line in a figure interactively.
vipblkdrawmarkers - VIPBLKCROSSHAIRS Mask dynamic dialog function for Draw Cross-hairs block
vipblkdrawshapes - VIPBLKROIDISPLAY Mask dynamic dialog function for Draw Shapes blocku
cw1dmngr - Continuous wavelet 1-D drawing manager.
drawtree - Draw wavelet packet decomposition tree.
wp1ddraw - Wavelet packets 1-D drawing manager.
wp2ddraw - Wavelet packets 2-D drawing manager.