Calculate the energy stored in Capacitor and Inductor

[ckboii89]

Homework Statement

A circuit consists of an 800mH inductor, a 20mF capacitor, and a switch, all in series.The capacitor is charged with an initial charge charge of Q = 400mC, and the switch is closed at t= 0.
Calculate the energy stored in the Inductor and Capacitor at t = 100ms.

Homework Equations

U= 1/2LI^2 + 1/2Q^2/c
I=Q/(LC)^1/2

The Attempt at a Solution

I= 3.16A
U=7.94J, there is no anwser key, it is a past exam that i do not have a key for. I feel i may have done this incorrectly since its asking for at t = 100ms, and U as a function of time is a sin/cos graph...

 

[gneill]

Homework Statement

Calculate the energy stored in Capacitor and Inductor at t=100ms

Homework Equations

Qo^2/2C[cos^2(wt+phi)+sin^2(wt+phi)

The Attempt at a Solution

This is just one part of a practice exam, i just need a hint. Do i set phi to zero?
Calculated frequency,charge,ω

You haven't supplied a complete problem statement; there's no circuit or component values.
Your Relevant Equation isn't an equation.
Your Attempt at a Solution isn't an attempt at a solution; if you provide a complete problem statement and your attempt, then we will know how to help.