acosh

<?

$num = cosh(deg2rad(0));

$return = acosh($num);

echo $return;

0

<?

for($i = -180; $i <= 180; ++$i)
{
    $num = cosh(deg2rad($i));

    $return = acosh($num);

    echo "$i: $return" . PHP_EOL;
}

-180: 3.1415926535898
-179: 3.1241393610699
-178: 3.1066860685499
-177: 3.08923277603
-176: 3.07177948351
-175: 3.0543261909901
-174: 3.0368728984701
-173: 3.0194196059502
-172: 3.0019663134302
-171: 2.9845130209103
-170: 2.9670597283904
-169: 2.9496064358704
-168: 2.9321531433505
-167: 2.9146998508305
-166: 2.8972465583106
-165: 2.8797932657906
-164: 2.8623399732707
-163: 2.8448866807508
-162: 2.8274333882308
-161: 2.8099800957109
-160: 2.7925268031909
-159: 2.775073510671
-158: 2.757620218151
-157: 2.7401669256311
-156: 2.7227136331112
-155: 2.7052603405912
-154: 2.6878070480713
-153: 2.6703537555513
-152: 2.6529004630314
-151: 2.6354471705114
-150: 2.6179938779915
-149: 2.6005405854716
-148: 2.5830872929516
-147: 2.5656340004317
-146: 2.5481807079117
-145: 2.5307274153918
-144: 2.5132741228718
-143: 2.4958208303519
-142: 2.4783675378319
-141: 2.460914245312
-140: 2.4434609527921
-139: 2.4260076602721
-138: 2.4085543677522
-137: 2.3911010752322
-136: 2.3736477827123
-135: 2.3561944901923
-134: 2.3387411976724
-133: 2.3212879051525
-132: 2.3038346126325
-131: 2.2863813201126
-130: 2.2689280275926
-129: 2.2514747350727
-128: 2.2340214425527
-127: 2.2165681500328
-126: 2.1991148575129
-125: 2.1816615649929
-124: 2.164208272473
-123: 2.146754979953
-122: 2.1293016874331
-121: 2.1118483949131
-120: 2.0943951023932
-119: 2.0769418098733
-118: 2.0594885173533
-117: 2.0420352248334
-116: 2.0245819323134
-115: 2.0071286397935
-114: 1.9896753472735
-113: 1.9722220547536
-112: 1.9547687622336
-111: 1.9373154697137
-110: 1.9198621771938
-109: 1.9024088846738
-108: 1.8849555921539
-107: 1.8675022996339
-106: 1.850049007114
-105: 1.832595714594
-104: 1.8151424220741
-103: 1.7976891295542
-102: 1.7802358370342
-101: 1.7627825445143
-100: 1.7453292519943
-99: 1.7278759594744
-98: 1.7104226669544
-97: 1.6929693744345
-96: 1.6755160819146
-95: 1.6580627893946
-94: 1.6406094968747
-93: 1.6231562043547
-92: 1.6057029118348
-91: 1.5882496193148
-90: 1.5707963267949
-89: 1.553343034275
-88: 1.535889741755
-87: 1.5184364492351
-86: 1.5009831567151
-85: 1.4835298641952
-84: 1.4660765716752
-83: 1.4486232791553
-82: 1.4311699866354
-81: 1.4137166941154
-80: 1.3962634015955
-79: 1.3788101090755
-78: 1.3613568165556
-77: 1.3439035240356
-76: 1.3264502315157
-75: 1.3089969389957
-74: 1.2915436464758
-73: 1.2740903539559
-72: 1.2566370614359
-71: 1.239183768916
-70: 1.221730476396
-69: 1.2042771838761
-68: 1.1868238913561
-67: 1.1693705988362
-66: 1.1519173063163
-65: 1.1344640137963
-64: 1.1170107212764
-63: 1.0995574287564
-62: 1.0821041362365
-61: 1.0646508437165
-60: 1.0471975511966
-59: 1.0297442586767
-58: 1.0122909661567
-57: 0.99483767363677
-56: 0.97738438111682
-55: 0.95993108859688
-54: 0.94247779607694
-53: 0.92502450355699
-52: 0.90757121103705
-51: 0.89011791851711
-50: 0.87266462599716
-49: 0.85521133347722
-48: 0.83775804095728
-47: 0.82030474843734
-46: 0.80285145591739
-45: 0.78539816339745
-44: 0.7679448708775
-43: 0.75049157835756
-42: 0.73303828583762
-41: 0.71558499331768
-40: 0.69813170079773
-39: 0.68067840827779
-38: 0.66322511575785
-37: 0.6457718232379
-36: 0.62831853071796
-35: 0.61086523819802
-34: 0.59341194567807
-33: 0.57595865315813
-32: 0.55850536063819
-31: 0.54105206811824
-30: 0.5235987755983
-29: 0.50614548307836
-28: 0.48869219055841
-27: 0.47123889803847
-26: 0.45378560551853
-25: 0.43633231299858
-24: 0.41887902047864
-23: 0.4014257279587
-22: 0.38397243543875
-21: 0.36651914291881
-20: 0.34906585039887
-19: 0.33161255787892
-18: 0.31415926535898
-17: 0.29670597283904
-16: 0.27925268031909
-15: 0.26179938779915
-14: 0.24434609527921
-13: 0.22689280275926
-12: 0.20943951023932
-11: 0.19198621771938
-10: 0.17453292519943
-9: 0.15707963267949
-8: 0.13962634015955
-7: 0.1221730476396
-6: 0.10471975511966
-5: 0.087266462599717
-4: 0.069813170079772
-3: 0.052359877559828
-2: 0.034906585039886
-1: 0.017453292519938
0: 0
1: 0.017453292519938
2: 0.034906585039886
3: 0.052359877559828
4: 0.069813170079772
5: 0.087266462599717
6: 0.10471975511966
7: 0.1221730476396
8: 0.13962634015955
9: 0.15707963267949
10: 0.17453292519943
11: 0.19198621771938
12: 0.20943951023932
13: 0.22689280275926
14: 0.24434609527921
15: 0.26179938779915
16: 0.27925268031909
17: 0.29670597283904
18: 0.31415926535898
19: 0.33161255787892
20: 0.34906585039887
21: 0.36651914291881
22: 0.38397243543875
23: 0.4014257279587
24: 0.41887902047864
25: 0.43633231299858
26: 0.45378560551853
27: 0.47123889803847
28: 0.48869219055841
29: 0.50614548307836
30: 0.5235987755983
31: 0.54105206811824
32: 0.55850536063819
33: 0.57595865315813
34: 0.59341194567807
35: 0.61086523819802
36: 0.62831853071796
37: 0.6457718232379
38: 0.66322511575785
39: 0.68067840827779
40: 0.69813170079773
41: 0.71558499331768
42: 0.73303828583762
43: 0.75049157835756
44: 0.7679448708775
45: 0.78539816339745
46: 0.80285145591739
47: 0.82030474843734
48: 0.83775804095728
49: 0.85521133347722
50: 0.87266462599716
51: 0.89011791851711
52: 0.90757121103705
53: 0.92502450355699
54: 0.94247779607694
55: 0.95993108859688
56: 0.97738438111682
57: 0.99483767363677
58: 1.0122909661567
59: 1.0297442586767
60: 1.0471975511966
61: 1.0646508437165
62: 1.0821041362365
63: 1.0995574287564
64: 1.1170107212764
65: 1.1344640137963
66: 1.1519173063163
67: 1.1693705988362
68: 1.1868238913561
69: 1.2042771838761
70: 1.221730476396
71: 1.239183768916
72: 1.2566370614359
73: 1.2740903539559
74: 1.2915436464758
75: 1.3089969389957
76: 1.3264502315157
77: 1.3439035240356
78: 1.3613568165556
79: 1.3788101090755
80: 1.3962634015955
81: 1.4137166941154
82: 1.4311699866354
83: 1.4486232791553
84: 1.4660765716752
85: 1.4835298641952
86: 1.5009831567151
87: 1.5184364492351
88: 1.535889741755
89: 1.553343034275
90: 1.5707963267949
91: 1.5882496193148
92: 1.6057029118348
93: 1.6231562043547
94: 1.6406094968747
95: 1.6580627893946
96: 1.6755160819146
97: 1.6929693744345
98: 1.7104226669544
99: 1.7278759594744
100: 1.7453292519943
101: 1.7627825445143
102: 1.7802358370342
103: 1.7976891295542
104: 1.8151424220741
105: 1.832595714594
106: 1.850049007114
107: 1.8675022996339
108: 1.8849555921539
109: 1.9024088846738
110: 1.9198621771938
111: 1.9373154697137
112: 1.9547687622336
113: 1.9722220547536
114: 1.9896753472735
115: 2.0071286397935
116: 2.0245819323134
117: 2.0420352248334
118: 2.0594885173533
119: 2.0769418098733
120: 2.0943951023932
121: 2.1118483949131
122: 2.1293016874331
123: 2.146754979953
124: 2.164208272473
125: 2.1816615649929
126: 2.1991148575129
127: 2.2165681500328
128: 2.2340214425527
129: 2.2514747350727
130: 2.2689280275926
131: 2.2863813201126
132: 2.3038346126325
133: 2.3212879051525
134: 2.3387411976724
135: 2.3561944901923
136: 2.3736477827123
137: 2.3911010752322
138: 2.4085543677522
139: 2.4260076602721
140: 2.4434609527921
141: 2.460914245312
142: 2.4783675378319
143: 2.4958208303519
144: 2.5132741228718
145: 2.5307274153918
146: 2.5481807079117
147: 2.5656340004317
148: 2.5830872929516
149: 2.6005405854716
150: 2.6179938779915
151: 2.6354471705114
152: 2.6529004630314
153: 2.6703537555513
154: 2.6878070480713
155: 2.7052603405912
156: 2.7227136331112
157: 2.7401669256311
158: 2.757620218151
159: 2.775073510671
160: 2.7925268031909
161: 2.8099800957109
162: 2.8274333882308
163: 2.8448866807508
164: 2.8623399732707
165: 2.8797932657906
166: 2.8972465583106
167: 2.9146998508305
168: 2.9321531433505
169: 2.9496064358704
170: 2.9670597283904
171: 2.9845130209103
172: 3.0019663134302
173: 3.0194196059502
174: 3.0368728984701
175: 3.0543261909901
176: 3.07177948351
177: 3.08923277603
178: 3.1066860685499
179: 3.1241393610699
180: 3.1415926535898