How can I solve a Heaviside function in MATLAB R2017b ?

i found a problem in heaviside(t-10) but when be in heaviside(10) it solve it !!

[ysm,xsm]=lsim(Asm,Gsm,H,zeros(k,r),5*u*heaviside(t-10),t,x0);

[yopt,xopt]=lsim(A-B*Kopt,G,H,zeros(k,r),5*u*heaviside(t-10),t,x0);

but I always get an error sound like

error using * Inner matrix dimensions must agree. I was trying to rewrite an expression like this:

Answer 1

[Walter Roberson]

5.*u.*heaviside(t-10)

[mohammed lubbad]

Thank you Walter you made my day grateful

[mohammed lubbad]

walter

do you have coder about sliding mode

[Walter Roberson]

I do not have any code about sliding mode, sorry.