quick easy question

im trying to write an rlc script, and it doesn't like my Vc line. what is my error? i've already established alpha omega and t.

if (Alpha^2 < Omega0^2);
Omega_d = sqrt(Omega0^2 - Alpha^2);
% Frequency of sin(wt) term
fprintf('The Circuit is UNDERDAMPED! [alpha<omega]\r\n');
B1 = -Vb;
B2 = ((Alpha*B1)/Omega_d);
Vc = 10 + (B1*cos*(Omega_d*t) + B2*sin*(Omega_d*t))*(exp(-Alpha*t));
plot(t, Vc, 'blue'); %plot the underdamped case in blue
end

Answer 1

[Dr. Seis]

It looks like "t" is an array of numbers, therefore you need to incorporate a "." before you multiply "(B1*cos*(Omega_d*t) + B2*sin*(Omega_d*t))" and "(exp(-Alpha*t))" to produce element-by-element multiplication. I.e.:

Vc = 10 + (B1*cos(Omega_d*t) + B2*sin(Omega_d*t)).*(exp(-Alpha*t));

Also, you have an "*" between you trig functions. Remove the "*" between the "cos" and "(Omega_d*t)" and similarly with the "sin" and "(Omega_d*t)"

Answer 2

[katerina jablonski]

here is the error response. i tried the "." and it still doesn't like it! frustrating. i don't really know how to use matlab, and our teacher is not helpful.

??? Error using ==> cos Not enough input arguments.

Error in ==> ANOTHERTRY at 65 Vc = 10 + (B1*cos*(Omega_d*t) + B2*sin*(Omega_d*t)).*(exp(-Alpha*t));

[Dr. Seis]

Oh heck... sorry I glazed over that one. Remove the "*" between the "cos" and "(Omega_d*t)" and similarly with the "sin" and "(Omega_d*t)"