 In this video we'll be looking at the instantaneous values and what we mean by that is we can calculate at any given point along this waveform what the value of current or voltage will be. So that's a very simple way of doing this is we can use the formula. The sine theta times the peak value equals the instantaneous value. So again using this formula here we can calculate at any given point along this waveform. It doesn't matter if it's 45 degrees 45.73692.154329 or you got any value along any point of this waveform we can calculate out exactly what that is. Let's take a look at examples. So let's say I have a peak value of current in this case of 50 amps. I want to figure out what the value of current is at 25 degrees into the waveform. I would just go the sine of 25 degrees times the 50 amps equals 21.1 amps. So we could calculate out where that is. Now also we could use this formula sine theta times peak equals instantaneous to figure out at what angles certain voltages will occur. So what angles and watch for that angles we'll talk about that in a second. Would you have an instantaneous value of 450 volts if the sine wave had a peak value of 725? So again we're using what we know sine theta times the peak value of 725 gives us an instantaneous value of 450. We're going to transpose that 725 out of this side whatever we do to one side of the equation we do to the other. So sine of theta is equal to 450 divided by 725. The sine of theta is equal to 0.621. Now we need to get this theta alone. We're going to inverse sine this side then we're going to also inverse sine that side whatever you do to one side of the equation you do to the other. We end up with an angle of 38.4 degrees meaning that when this sine wave has 450 volts on it it is at 38.4 degrees into its cycle. So that's our angle number one is 38.4 degrees. So at 38.4 degrees this voltage occurs. Now you notice though that this point here is generally going to be roughly the same value as that point there. So you could say that you have that value and that value will be equal meaning that it occurs two times but oh let's take a look down here it also could occur at that point or that point yes in the negative direction but you're still going to have the same idea for the values. So let's take a look we mean here. If angle one is at 38.4 degrees into the cycle we could say that 180 degrees which is here and if we go back 38.4 we'll get us the same value. So we do that and we calculate that out to be 141.6 degrees. Into the third angle if we start at 180 degrees and we push our way into 38.4 degrees we're going to get the same value. So 180 plus 38.4 equals 218.4 degrees and I think you're picking up what I'm putting down here 360 degrees we're at the end of the cycle but if we push it back 38.4 degrees we're going to get the same value. So we end up with 321.6 degrees. So that value occurs four times in this complete cycle. So at 38.4 at 141.6 at 218.4 and at 321.6. So watch to see if you're being asked for angles or just one angle. If it's just one angle you can pick any one of these four. Generally though we're going to ask you for the four angles.