difficult inequality to solve

1 ビュー (過去 30 日間)
bk97
bk97 2017 年 1 月 25 日
コメント済み: Walter Roberson 2017 年 1 月 26 日
abs((cos(x)+1/2*x^2)-1)*x^4)<=1/24, does anybody have any idea how to solve this on matlab or write down some possible codes?

採用された回答

Niels
Niels 2017 年 1 月 25 日
編集済み: Niels 2017 年 1 月 25 日
since your function is even it is symmetric and it is monotone for x>0 or x<0
use fzero
>> f=@(x)((cos(x)+1./2.*x.^2)-1).*x.^4 - 1/24 % subtract the value to transform it into an issue of roots
>> solution=abs(fzero(f,0))
solution =
1.0042
>> range=[-solution solution]
range =
-1.0042 1.0042
  19 件のコメント
Walter Roberson
Walter Roberson 2017 年 1 月 26 日
The +/- -1.004205445912837 I show occurs when the imaginary component is 0. It is a higher precision version of the value that Niels posted. The code Niels posted is fine.

サインインしてコメントする。

その他の回答 (0 件)

タグ

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by