# No lines on my graph

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Yaneli Rubio on 24 Oct 2020
Commented: Star Strider on 27 Oct 2020 at 16:12
Hello,
I have gone through multiple of the post with similar problems without any luck. Can some one help? Why do no lines show on my graph?
% Assumened Values
Ti=20;
Tamb=38;
h=5.2;
d=1035; %density
c=3350;
k=0.62;
t=3600; %time in seconds
V=3/4*pi*r^3;
m=d*V
a= 2.3184*10^-5;
A=4*pi*r^2;
% for spherical system
Lc=r/3
%Biot Number
Bi= h*Lc/k
% Temperature after 60 minutes
T=Tamb+(exp((-h*A)/(m*c)*t)*(Ti-Tamb))
%plot T vs t
x=[0:100:3600]; %time on x-axis
plot(t,T), xlabel('time'), ylabel('Temperature'), title('Temperature vs Time') Star Strider on 24 Oct 2020
I suspect that ‘t’ is supposed to be a vector:
t=0:3600; %time in seconds
and then using element-wise division in the ‘T’ assignment:
T=Tamb+(exp((-h*A)./(m*c)*t)*(Ti-Tamb));
and the plotted ‘T’ as a function of ‘t’ curve magickally appears!

Yaneli Rubio on 27 Oct 2020 at 15:39
I can't believe I missed that. Thank you so much!
Star Strider on 27 Oct 2020 at 16:12
As always, my pleasure!
No worries! I’ve done similar things and I’m certain others have as well!