# Second Order Circuit Question

Discussion in 'Homework Help' started by Digit0001, May 21, 2011.

1. ### Digit0001 Thread Starter Member

Mar 28, 2010
89
0
Hi

Can someone explain to me how they got tan() in the last couple of lines, when they are finding the peak time.
View attachment tut7_sols.doc

P.S

2. ### jegues Well-Known Member

Sep 13, 2010
735
43
It seems as though they took the expression for $\frac{dv_{c}}{dt}$ (i.e. equation (2)), and divided it by, $-5cos(21.794t_{o}),$ which is reasonable because the other side of the equation is simply 0.

I assume they are neglecting the exponential terms because $t_{o}$ is very small. By this I mean,

$e^{t_{o}}, \quad t_{o} \approx 0 \Rightarrow e^{t_{o}} \approx 1$