Use php+mysql to make a powerful online calculator_PHP tutorial

//
$db that links the database =mysql_connect("localhost","root","123");
header("Content-Type:text/html;charset=GB2312");
$str=iconv('utf-8', 'gbk',trim($_POST['t_ask']));
$str=str_replace(" ","",str_replace("rn","",$str));
$str= str_replace("（","(",$str);
$str=str_replace(")",")",$str);
/*Trigonometric function replacement*/
$str= preg_replace("/sin((.*))/is","sin(${1}*pi()/180)",$str);//Replace sin
$str=preg_replace("/cos ((.*))/is","cos(${1}*pi()/180)",$str);//Replace cos
$str=preg_replace("/tan((.*) )/is","tan(${1}*pi()/180)",$str);//Replace tan
$str=preg_replace("/cot((.*))/is", "1/tan(${1}*pi()/180)",$str);//Replace cotangent
$str=preg_replace("/asin((.*))/is","asin (${1}/pi()*180)*180/pi()",$str);//arcsine
$str=preg_replace("/acos((.*))/is"," acos(${1}/pi()*180)*180/pi()",$str);//Inverse cosine
$str=preg_replace("/atan((.*))/is", "atan(${1}/pi()*180)*180/pi()",$str);//Replace arctangent
$sql="select ".$str;
$res= mysql_query($sql,$db) or die('The formula you entered is wrong');
$rs=mysql_fetch_array($res);
echo $rs[0];
?>

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Handwriting input calculator

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Here you can calculate by handwriting, why not give it a try! Return to homepage

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Calculation formula:
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Instructions: Trigonometric functions: sin(60) sine cos(60) cosine tan (60) Tangent cot(60) Cotangent asin(0.5) Arcsine acos(0.5) Arccosine atan(0.5) Arctangent abs(-1) =1 absolute value ceil(0.1)=1 into one Exponential logarithm exp(float arg)// Calculatee(natural logarithm The exponent of the base) log(10,100)=2//natural logarithm pow(2,4)=16 exponent sqrt(4)=2 square root