Okay, I have this so far
z= -1+7i
As far as what I have for polar coordinate equation, this is it:
z= 6.93(cos180+ i sin?)
My problem is that 7 cannot be converted into an angle.
What would I do for this?
You should know that the argument of z = a + ib is where you have to be careful what quadrant (and hence value) you choose for ..... A simple argand diagram showing z = a + ib will help you make that decision.
For the question you've posted, .
An argand diagram easily shows that z = -1 + 7i lies in the 2nd quadrant, so radians.
Therefore