Complex number

2009-02-07 9:03 pm
Express the complex number z = -5+12i in polar form.
ANS:
tan(arg z) = -12/5 ------------- 1
arg z = 1.97 ----------- 2
z = 13(cos 1.97 + i sin 1.97)
我想知 1 點變 2
明明 tan^(-1) [-12/5] = - 67. XXX
點解會係 1.97 ??
更新1:

係咪一定要用argand圖諗? 點解唔可以係 -67.3801 + 360 = 282.6198?

回答 (1)

2009-02-07 10:17 pm
✔ 最佳答案
tan^(-1) [-12/5] = - 67. 3801 degree
用argand圖諗﹐theta應是180-67.3801=112.6199 degree
再轉弧度
112.6199 degree
=112.6199 degree * 2phi radians/360 degrees
=1.97 radians
朋友學過弧度了嗎?

2009-02-07 14:52:58 補充:
0甘個complex number在第二象限是一個fact


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