Hint $1$for Part A$.$

At any given time, the voltages across the inductor, the capacitor and the resistor are:

vL$=$VLcos$($t$+$$2)$vL$=$VLcos$($t$+$$2)$

vC$=$VCcos$($t$$$2)$vC$=$VCcos$($t$$$2)$

vR$=$VRcos$($t$)$vR$=$VRcos$($t$)$

Using the information you have about vLvL and VLVL$,$ you can find the value of tt$,$ and use it in the expression for the voltage across the capacitor.

Hint $2$for Part A$.$

Remember to keep your calculator in radians.