Energy of an inductor and capacitor
Why isn't the frequency also included in the formulas?


These formulas are for the instantaneous energy. The energy stored in the inductor or capacitor at an exact moment in time. 

If an AC signal is applied, the stored energy will cycle at twice the signal frequency.


  As a higher frequency wave is more energetic than a low frequency wave.


A high frequency photon has more energy than a low frequency photon. But a classical wave is made up of many photons and it's certainly possible to have a low power wave at 100 GHz or a very high powered wave at a few millihertz or even deliver very high power at DC.