Calculate function with given t

clc
clear all
close all
syms t
A = [-1, 1, 0;
      1,-2, 1;
      0, 1, -1];
[P,D] = eig(A)
Phi = P*expm(D*t)*inv(P)
thetanot=[0.1;0.3;0.2]
t_t=Phi*thetanot
dt = 1/1000;
t = 0:dt:1000*dt;
S1=sum(t_t(1,1))

Where S1 =

How do I plot the S1 with t ?

Answer 1

[KSSV]

Read about fplot/ ezplot.

clc
clear all
close all
syms t
A = [-1, 1, 0;
      1,-2, 1;
      0, 1, -1];
[P,D] = eig(A)

P = 3×3

-0.4082 -0.7071 0.5774 0.8165 0.0000 0.5774 -0.4082 0.7071 0.5774

D = 3×3

-3.0000 0 0 0 -1.0000 0 0 0 -0.0000

Phi = P*expm(D*t)*inv(P)

Phi = 

σ3σ4−1538314690327739 G2 e−t40564819207303340847894502572032−σ1σ2σ4−4117251858840527 G2 e−t81129638414606681695789005144064−σ1σ4+6333629018233573058406165478453 e−t822752278660603021077484591278675252491367932816789931674304512+2 e−3 t3σ4+4117251858840527 G2 e−t81129638414606681695789005144064−σ1σ2σ4+1538314690327739 G2 e−t40564819207303340847894502572032−σ1σ3where  σ1=G2 G3 G6 e−3 t18  σ2=σ4−e−t2+e−3 t6  σ3=σ4+e−t2+e−3 t6  σ4=e−7734480885 t773712524553362671811952643

thetanot=[0.1;0.3;0.2]

thetanot = 3×1

0.1000 0.3000 0.2000

●

t_t=Phi*thetanot

t_t = 

σ2−e−t20+e−3 t20−σ3−σ1σ2+19000887054700719175218496435359 e−t8227522786606030210774845912786752524913679328167899316743045120+e−3 t5+1538314690327739 G2 e−t405648192073033408478945025720320−σ1σ2+e−t20+e−3 t20+σ3−σ1where  σ1=G2 G3 G6 e−3 t60  σ2=e−7734480885 t773712524553362671811952645  σ3=12351755576521581 G2 e−t811296384146066816957890051440640

dt = 1/1000;
t = 0:dt:1000*dt;
S1=sum(t_t(1,1)) ;
fplot(S1)