High School Formulas for the alternating current and voltage

[wolly]

Hi,I have found in my textbook the formulas for both current and voltage and I have no idea if they are right or wrong. Can someone help me with these formulas?
v=v0cos(wt)
i=i0cos(wt)
Is this correct? In google when I search for the answers I get something else:
v=v0sin(wt)
i=i0sin(wt)

 

[anuttarasammyak]

They are same sinusoidal function with only difference of phase.　
Fot t=0
The former v=v0 i=i0
The latter v=0 i=0

 

[Delta2]

Yes if you know abit of trigonometry it is $$\cos(\omega t)=\sin(\omega t+\frac{\pi}{2})=\sin(\omega(t+t_0))$$ where $t_0=\frac{\pi}{2\omega}$ the phase difference in seconds.