Int gives wrong answer
古いコメントを表示
syms x
f(x) = cos(x)*sin(x);
Fx = int(f,x)
Fx(x) =
sin(x)^2/2
while the correct answer is -cos(x)^2/2
3 件のコメント
Robin Merkle
2022 年 3 月 2 日
The answer is correct. d/dx sin^2(x)/2 = sin(x)cos(x).
Torsten
2022 年 3 月 2 日
Since sin(x)^2/2 = -cos(x)^2/2 + 1/2, both answers are correct.
Note that both answers only differ by a constant, namely 1/2.
Ali M
2022 年 3 月 5 日
回答 (1 件)
Walter Roberson
2022 年 3 月 2 日
0 投票
Remember that indefinite integration always has an implied "plus a constant". So any two results of int() that differ by a constant are the same integral result. And sin squared plus cos squared equals 1 so the two possibilities are the same up to the constant.
You can ask to rewrite() to 'cos'
カテゴリ
ヘルプ センター および File Exchange で Mathematics についてさらに検索
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!