028-PHP常用数学函数abs和acos和asin

<?php
    print(abs(-13));//打印绝对值

    // 从 -1 到1打印acos函数的值
    print("<TABLE BORDER="1">
");
    print("<TR><TH>x</TH><TH>acos(x)</TH></TR>
");
    for($index = -1; $index <= 1; $index += 0.25)
    {
        print("<TR>
");
        print("<TD>$index</TD>
");
        print("<TD>" . acos($index) . "</TD>
");
        print("</TR>
");
    }
    print("</TABLE>
");

    //  从 -1 到 1打印asin函数的值
    print("<TABLE BORDER="1">
");
    print("<TR><TH>x</TH><TH>asin(x)</TH></TR>
");
    for($index = -1; $index <= 1; $index += 0.25)
    {
        print("<TR>
");
        print("<TD>$index</TD>
");
        print("<TD>" . asin($index) . "</TD>
");
        print("</TR>
");
    }
    print("</TABLE>
");
?>