Find the product of z1 and z2, where z1 = 7(cos 40° + i sin 40°), and z2 = 6(cos 145° + i sin 145°)?
回答 (1)
2019-01-29 4:46 am
(cos(a) + i * sin(a)) * (cos(b) + i * sin(b)) = cos(a + b) + i * sin(a + b)
7 * 6 * (cos(40 + 145) + i * sin(40 + 145)) =>
42 * (cos(185) + i * sin(185)) =>
42 * (-cos(5) - i * sin(5)) =>
-42 * (cos(5) + i * sin(5))
7 * 6 * (cos(40 + 145) + i * sin(40 + 145)) =>
42 * (cos(185) + i * sin(185)) =>
42 * (-cos(5) - i * sin(5)) =>
-42 * (cos(5) + i * sin(5))
收錄日期: 2021-05-01 22:15:24
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20190128204334AAV32wG