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<?php function y($x) { return pow($x, 2);}function integrate($a, $b, $n) { $h = ($b-$a)/$n; $m = (1/2)*$h; $num = 0; for ($i = 1; $i <= $n-1; $i++) { $num += y($a + $i*$h); } return $m*(y($a) + y($b) + $num);}var_dump(integrate(1, 3, 100));

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34.47 ms | 402 KiB | 5 Q