getting the error please help

b4=0.1:0.001:1;
B=(20.*abs(b4))/3;
F1=(6/abs(b4)).*(sqrt(10^(-2)+B)+10^(-1));
F2=(6/abs(b4)).*(sqrt(10^(-4)+B)+10^(-2));
figure
plot(b4,F1,b4,F2)
xlabel('phase mismatch')
ylabel('GAIN FWM')

%%% ??? Error using ==> mldivide Matrix dimensions must agree.

Error in ==> UntitledFWM at 12 F1=(6/abs(b4)).*(sqrt(10^(-2)+B)+10^(-1));%%

Answer 1

[Azzi Abdelmalek]

Don't forget to use ./ instead of /

b4=0.1:0.001:1;
B=(20.*abs(b4))/3;
F1=(6./abs(b4)).*(sqrt(10^(-2)+B)+10^(-1));
F2=(6./abs(b4)).*(sqrt(10^(-4)+B)+10^(-2));
figure
plot(b4,F1,b4,F2)
xlabel('phase mismatch')
ylabel('GAIN FWM')

[abed]

thank you very much it worked when you told me wow but why??

[Azzi Abdelmalek]

for the same reason you wrote .* instead of *