1. The problem statement, all variables and given/known data Plot |z| vs. f(Hz) of the circuit. R=100, C=600 pf = 6E-12 F, L=10E-6 H . All elements of the circuit are in parallel. Also identify the resonant frequency. 2. Relevant equations ZR=R ZL=jwL ZC=1/(jwC)=-j/(wC) w=2(pi)f w0=1/sqrt(LC) f0=1/(2(pi)sqrt(LC)) G=1/R 3. The attempt at a solution Z1=ZR Z2=ZL Z3=ZC Zeq= 1/((1/R)+1/(jwL)+jwc) Switching to admittance and skipping a few steps, it can be found that Y=G + j * 2 * pi * f * C * (1 - (f0 / f) ^ 2) Z=R + 1 / (j * 2 * pi * f * C * (1-(f0 / f) ^ 2)) Z=100 + 1/(j * 2 * pi * f * 600E-12 *(1 - (2054681.48 / f) ^ 2) To plot, i used a few lines in matlab: f=linspace(0,4000000,100000); x=1i.*2.*pi.*(600.^(-12)); z=100+(1./(x.*f.*(1-((2054681.48./f).^2)))); plot=semilogx(z); The plot shows me a vertical line at f=100 My professor told us that the graph should be bell shaped, and i have no idea where i've gone wrong. Anyone see a mistake?