acos

<?

$num = cos(deg2rad(360));

$return = acos($num);

echo $return;

0

<?

for($i = 0; $i <= 360; ++$i)
{
    $num = cos(deg2rad($i));

    $return = acos($num);

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

0: 0
1: 0.017453292519942
2: 0.034906585039886
3: 0.052359877559831
4: 0.069813170079774
5: 0.087266462599716
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: 0.82030474843733
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
181: 3.1241393610699
182: 3.1066860685499
183: 3.08923277603
184: 3.07177948351
185: 3.0543261909901
186: 3.0368728984701
187: 3.0194196059502
188: 3.0019663134302
189: 2.9845130209103
190: 2.9670597283904
191: 2.9496064358704
192: 2.9321531433505
193: 2.9146998508305
194: 2.8972465583106
195: 2.8797932657906
196: 2.8623399732707
197: 2.8448866807508
198: 2.8274333882308
199: 2.8099800957109
200: 2.7925268031909
201: 2.775073510671
202: 2.757620218151
203: 2.7401669256311
204: 2.7227136331112
205: 2.7052603405912
206: 2.6878070480713
207: 2.6703537555513
208: 2.6529004630314
209: 2.6354471705114
210: 2.6179938779915
211: 2.6005405854716
212: 2.5830872929516
213: 2.5656340004317
214: 2.5481807079117
215: 2.5307274153918
216: 2.5132741228718
217: 2.4958208303519
218: 2.4783675378319
219: 2.460914245312
220: 2.4434609527921
221: 2.4260076602721
222: 2.4085543677522
223: 2.3911010752322
224: 2.3736477827123
225: 2.3561944901923
226: 2.3387411976724
227: 2.3212879051525
228: 2.3038346126325
229: 2.2863813201126
230: 2.2689280275926
231: 2.2514747350727
232: 2.2340214425527
233: 2.2165681500328
234: 2.1991148575129
235: 2.1816615649929
236: 2.164208272473
237: 2.146754979953
238: 2.1293016874331
239: 2.1118483949131
240: 2.0943951023932
241: 2.0769418098733
242: 2.0594885173533
243: 2.0420352248334
244: 2.0245819323134
245: 2.0071286397935
246: 1.9896753472735
247: 1.9722220547536
248: 1.9547687622336
249: 1.9373154697137
250: 1.9198621771938
251: 1.9024088846738
252: 1.8849555921539
253: 1.8675022996339
254: 1.850049007114
255: 1.832595714594
256: 1.8151424220741
257: 1.7976891295542
258: 1.7802358370342
259: 1.7627825445143
260: 1.7453292519943
261: 1.7278759594744
262: 1.7104226669544
263: 1.6929693744345
264: 1.6755160819146
265: 1.6580627893946
266: 1.6406094968747
267: 1.6231562043547
268: 1.6057029118348
269: 1.5882496193148
270: 1.5707963267949
271: 1.553343034275
272: 1.535889741755
273: 1.5184364492351
274: 1.5009831567151
275: 1.4835298641952
276: 1.4660765716752
277: 1.4486232791553
278: 1.4311699866354
279: 1.4137166941154
280: 1.3962634015955
281: 1.3788101090755
282: 1.3613568165556
283: 1.3439035240356
284: 1.3264502315157
285: 1.3089969389957
286: 1.2915436464758
287: 1.2740903539559
288: 1.2566370614359
289: 1.239183768916
290: 1.221730476396
291: 1.2042771838761
292: 1.1868238913561
293: 1.1693705988362
294: 1.1519173063163
295: 1.1344640137963
296: 1.1170107212764
297: 1.0995574287564
298: 1.0821041362365
299: 1.0646508437165
300: 1.0471975511966
301: 1.0297442586767
302: 1.0122909661567
303: 0.99483767363677
304: 0.97738438111682
305: 0.95993108859688
306: 0.94247779607694
307: 0.925024503557
308: 0.90757121103705
309: 0.89011791851711
310: 0.87266462599716
311: 0.85521133347722
312: 0.83775804095728
313: 0.82030474843733
314: 0.80285145591739
315: 0.78539816339745
316: 0.76794487087751
317: 0.75049157835756
318: 0.73303828583762
319: 0.71558499331768
320: 0.69813170079773
321: 0.68067840827779
322: 0.66322511575785
323: 0.6457718232379
324: 0.62831853071796
325: 0.61086523819802
326: 0.59341194567807
327: 0.57595865315813
328: 0.55850536063819
329: 0.54105206811824
330: 0.5235987755983
331: 0.50614548307836
332: 0.48869219055841
333: 0.47123889803847
334: 0.45378560551853
335: 0.43633231299858
336: 0.41887902047864
337: 0.4014257279587
338: 0.38397243543875
339: 0.36651914291881
340: 0.34906585039887
341: 0.33161255787892
342: 0.31415926535898
343: 0.29670597283904
344: 0.27925268031909
345: 0.26179938779915
346: 0.24434609527921
347: 0.22689280275926
348: 0.20943951023932
349: 0.19198621771938
350: 0.17453292519943
351: 0.15707963267949
352: 0.13962634015955
353: 0.1221730476396
354: 0.10471975511966
355: 0.087266462599716
356: 0.069813170079774
357: 0.052359877559829
358: 0.034906585039886
359: 0.017453292519942
360: 0