190001 求平方根近似值已知任意一个正数

<?php
header('Content-Type: text/html; charset=utf-8');
define ('ROOT', $_SERVER['DOCUMENT_ROOT']);
include ROOT.'/assets/php/head.php';

$tit= '求平方根近似值已知任意一个正数';
//正数：17
$val='17';
$img='';

//调用方法
mill($val,$img,$tit);

//mill 是磨粉机的方法
function mill($val,$img,$tit){
    //初始化
    include ROOT.'/assets/php/init.php';
    imgt($img,$tit);

    //设置小数点保留位数 
    bcscale (2);
    //$pi = round(pi(),2);
    
    //以空格分割成数值
    $vals = expl($val);
    $n = evev($vals[0]);

    //已知条件
    $know = array();
    array_push($know, $val);
    $v0 = eveq($vals[0]);
    array_push($know, "正数：$v0");

    //计算步骤
    $step = array();
    array_push($step, "拆分{$n}：");
    $a = bcsqrt($n,0);
    $aa = $a*$a;
    $b = $n-$aa;
    array_push($step, "{$math['eq']} $aa{$math['add']}$b");
    array_push($step, "{$math['eq']} $a{$math['sup2']}{$math['add']}$b");

    array_push($step, "求{$n}平方根近似值：");
    array_push($step, "{$math['eq']} $a{$math['add']}{$math['lsqb']}$b{$math['div']}{$math['lpar']}2{$math['mul']}$a{$math['rpar']}{$math['rsqb']}");
    $a2 = 2*$a;
    array_push($step, "{$math['eq']} $a{$math['add']}{$math['lpar']}$b{$math['div']}$a2{$math['rpar']}");
    $ba2 = $b/$a2;
    array_push($step, "{$math['eq']} $a{$math['add']}$ba2");
    $m = $a+$ba2;
    array_push($step, "{$math['eq']} $m");

    array_push($step, "验算：");
    array_push($step, "{$math['eq']} {$math['root2']}$n");
    $sqrtn = bcsqrt($n,12);
    array_push($step, "{$math['eq']} $sqrtn");

    //算出结果
    $ends = array();
    array_push($ends, "拆分任意一个正数：$a{$math['sup2']}{$math['add']}$b");
    $roundm = round($m,3);
    array_push($ends, "平方根近似值：$roundm");
    $roundsqrtn = round($sqrtn,5);
    array_push($ends, "验算：$roundsqrtn");

    //公式表示
    $home = array();
    array_push($home, "拆分任意一个正数：n{$math['eq']}a{$math['sup2']}{$math['add']}b");
    array_push($home, "平方根近似值：{$math['root2']}n{$math['eq']}a{$math['add']}{$math['lpar']}b{$math['sol']}2a{$math['rpar']}");

    //解释说明
    $info = array();
    array_push($info, "求平方根近似值公式只适用于正数。");
    array_push($info, "正数的解释：数学上称凡大于零的数为正数。");

    know($know);
    ends($ends);
    home($home);
    step($step);
    info($info);
}
?>
<?php include ROOT.'/assets/php/foot.php';
//写下笔记
$note = array();
note($note);
?>