how can make it variable not given data

Pg=9.4; % Gas pressure (MPa) ETA_MEC=.9; Bpower=58823.53; %Break power (Watt) N=2500; % Speed (rpm) Z=4; %No.Cylinders Taw=2; Sigma_1=45; %Allowable circumferential stress (MPa) C=.01; %Constant in Thickness of cyl. head Equation Ipower=Bpower/ETA_MEC; n=N/Taw; Pm=Pg/9; %Mean Effective Pressure(Mpa) D=((Ipower*60*1000*4)/(Pm*1.5*pi*n*Z))^(1/3) % Bore diamter (mm) Lst=1.5*D %Stroke length(mm) t=.045*D+1.6 % thickness of cylinder Sigma_c=((D*Pg)/(2*t)) % circumferential Stress t_head=D*(C*Pg/Sigma_1)^.5 %thickness of cyliunder head

[Image Analyst]

Read this, then fix the formatting. Then read this and explain what you want to make a variable. As far as I know all those things are variables, though some of the variables may be constant, or user-supplied. Not sure which variable name you're talking about.

Answer 1

[Image Analyst]

This sounds remarkably similar to Vivie's question: http://www.mathworks.com/matlabcentral/answers/213650-i-need-serious-help-please If it's the same homework problem, you will find help there.