Question

4.1 The current in an ac circuit at any time 𝑡 seconds is given by: 𝑖(𝑡) = 120 sin(100𝜋𝑡 +
0.36) amperes. Determine:
4.1.1 The peak value, the periodic time, the frequency and phase angle relative to
120 sin(100𝜋𝑡). 
4.1.2 The value of the current when 𝑡 = 0. 
4.1.3 The time when the current first reaches 60 A. 
4.1.4 The time when the current is first at maximum.