Hi can someone help me with these following application of differentiation

like please kindly explain step by step like how to start and what formula you guys use cause I'm super lost :(

I seriously need help

Really hope you don't mind helping me and explaining it to me slowly.... thank you in advance

Section B: Optimisation Problems (MaximaIMinima problems) 1. The vibration frequency f (in kilohertz) of a quartz oscillator is given by f = 5433'2 4d + 384 where d is its thickness (in micrometres). Find the crystal thickness for which the vibration frequency is minimum. The power consumption H (in kwh) varies according to the equation H = 3V 2V2 + 416 where V is the voltage. Find the maximum value of the power consumption. The charge (,1 (in coulombs) transmitted through a circuit varies according to the equation 4! q _ 4:2 +1 and the time at which it occurs. where t is the time in seconds. Determine the maximum charge of the circuit