The plots shown here are the voltage across and the current
     The plots shown here are the voltage across and the current through an ideal capacitor. Determine the capacitance.   
  
  Solution
V(t) = voltage across capacitor
=-3 ,0<t<=1
=-3+ (t-1) , 1<t<=3
=-1, t>3
i(t)= current
=50 mA, 1<t<3
=0 , else
As we know, i= C*dV/dt
i= C*1 , 1<t<3
50 mA= C*1
C= 50 mF

