2arctan(二分之根號二)=cos___???
___是填數字(只是分母)
arc是咩意思
2arctan
2006-11-27 12:59 am
回答 (1)
2006-11-28 12:59 am
✔ 最佳答案
Arctan is the inverse of tan.If y = tan (x)
x = arctan(y)
Now let cos(y) = 2arctan(√2)
So, tan[cos(y)/2] = √2
{tan[cos(y)/2]}^2 = 2
{sin[cos(y)/2]}^2 = 2{cos[cos(y)/2]}^2
1 - {cos[cos(y)/2]}^2 = 2{cos[cos(y)/2]}^2
3{cos[cos(y)/2]}^2 = 1
cos[cos(y)/2] = 1/√3
cos(y) = 2arccos(1/√3)
收錄日期: 2021-04-13 14:41:23
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061126000051KK03663