atan2 - Český PHP manuál

Funkce atan2 v PHP vrací hodnotu goniometrické funkce arkus tangens. Počítá však se dvěma hodnotami a je to jako bychom počítali arkus tangens y/x s tím rozdílem, že funkce podle znamének vybere kvadrant.

Vstupní hodnoty

Výstupní hodnota

(float) Výsledek v radiánech

Ukázkový kód

<?php
$tanValues = array();
for ($i = 0; $i <= 180; $i = $i + 15) {
    $rand = rand(0, 180);
    $tan = tan(deg2rad($i));
    $tanRand = tan(deg2rad($rand));
    echo "tan(" . $i . "°) = $tan <br />
    tan(" . $rand . "°) = $tanRand <br />
    atan(" . $tan . ", " . $tanRand . ") = " . rad2deg(atan2($tan, $tanRand)) . "°<br />
    ================================<br />";
}
?>

Výstup kódu

tan(0°) = 0
tan(20°) = 0.3639702342662
atan(0, 0.3639702342662) = 0°
================================
tan(15°) = 0.26794919243112
tan(68°) = 2.4750868534163
atan(0.26794919243112, 2.4750868534163) = 6.178692287137°
================================
tan(30°) = 0.57735026918963
tan(71°) = 2.9042108776758
atan(0.57735026918963, 2.9042108776758) = 11.24367666375°
================================
tan(45°) = 1
tan(135°) = -1
atan(1, -1) = 135°
================================
tan(60°) = 1.7320508075689
tan(10°) = 0.17632698070846
atan(1.7320508075689, 0.17632698070846) = 84.18717608711°
================================
tan(75°) = 3.7320508075689
tan(150°) = -0.57735026918963
atan(3.7320508075689, -0.57735026918963) = 98.793976886997°
================================
tan(90°) = 1.6331239353195E+16
tan(158°) = -0.40402622583516
atan(1.6331239353195E+16, -0.40402622583516) = 90°
================================
tan(105°) = -3.7320508075689
tan(131°) = -1.150368407221
atan(-3.7320508075689, -1.150368407221) = -107.13140597618°
================================
tan(120°) = -1.7320508075689
tan(139°) = -0.86928673781623
atan(-1.7320508075689, -0.86928673781623) = -116.65129340568°
================================
tan(135°) = -1
tan(168°) = -0.21255656167002
atan(-1, -0.21255656167002) = -102°
================================
tan(150°) = -0.57735026918963
tan(139°) = -0.86928673781623
atan(-0.57735026918963, -0.86928673781623) = -146.40925870461°
================================
tan(165°) = -0.26794919243112
tan(128°) = -1.2799416321931
atan(-0.26794919243112, -1.2799416321931) = -168.17617731843°
================================
tan(180°) = -1.2246467991474E-16
tan(172°) = -0.14054083470239
atan(-1.2246467991474E-16, -0.14054083470239) = -180°
================================

Související funkce

• deg2rad
• tan
• atan
• tanh
• atanh