greatwhiteshark
Full Member
- Joined
- May 8, 2005
- Messages
- 279
d = degrees
If z = 3(cos20d + i sin20d) and w = 5(cos100d + i sin100d), find the following: zw and z/w.
I understand how to find z times w or zw but get lost after a certain step in terms of dividing z by w or z/w.
z/w = 3(cos20d + isin20d)/5(cos100d + i sin100d)
z/w = 3/5[cos(20d - 100d) + i sin(20d -100d)]
z/w = 3/5[cos(-80) + 1 sin(-80)]
After this step, the book's answer is
z/w = 3/5(cos280d + i sin280d)
Then it states: "Argument must lie between 0d and 360d."
Two question:
1) Where did 280 degrees come from in the final step?
2) What does the author mean by "Argument must lie between 0d and 360d"?
If z = 3(cos20d + i sin20d) and w = 5(cos100d + i sin100d), find the following: zw and z/w.
I understand how to find z times w or zw but get lost after a certain step in terms of dividing z by w or z/w.
z/w = 3(cos20d + isin20d)/5(cos100d + i sin100d)
z/w = 3/5[cos(20d - 100d) + i sin(20d -100d)]
z/w = 3/5[cos(-80) + 1 sin(-80)]
After this step, the book's answer is
z/w = 3/5(cos280d + i sin280d)
Then it states: "Argument must lie between 0d and 360d."
Two question:
1) Where did 280 degrees come from in the final step?
2) What does the author mean by "Argument must lie between 0d and 360d"?