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FACESOHO知行者
心灵
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源代码
运行
保存
"); echo(acos(-0.4) . "
"); echo(acos(0) . "
"); echo(acos(-1) . "
"); echo(acos(1) . "
"); echo(acos(2)); ?>
运行结果
0.87629806116834
1.9823131728624
1.5707963267949
3.1415926535898
0
NAN