Metamath Proof Explorer


Theorem dvasin

Description: Derivative of arcsine. (Contributed by Brendan Leahy, 18-Dec-2018)

Ref Expression
Hypothesis dvasin.d D = −∞ 1 1 +∞
Assertion dvasin D arcsin D = x D 1 1 x 2

Proof

Step Hyp Ref Expression
1 dvasin.d D = −∞ 1 1 +∞
2 df-asin arcsin = x i log i x + 1 x 2
3 2 reseq1i arcsin D = x i log i x + 1 x 2 D
4 difss −∞ 1 1 +∞
5 1 4 eqsstri D
6 resmpt D x i log i x + 1 x 2 D = x D i log i x + 1 x 2
7 5 6 ax-mp x i log i x + 1 x 2 D = x D i log i x + 1 x 2
8 3 7 eqtri arcsin D = x D i log i x + 1 x 2
9 8 oveq2i D arcsin D = dx D i log i x + 1 x 2 d x
10 cnelprrecn
11 10 a1i
12 5 sseli x D x
13 ax-icn i
14 mulcl i x i x
15 13 14 mpan x i x
16 ax-1cn 1
17 sqcl x x 2
18 subcl 1 x 2 1 x 2
19 16 17 18 sylancr x 1 x 2
20 19 sqrtcld x 1 x 2
21 15 20 addcld x i x + 1 x 2
22 12 21 syl x D i x + 1 x 2
23 asinlem x i x + 1 x 2 0
24 12 23 syl x D i x + 1 x 2 0
25 22 24 logcld x D log i x + 1 x 2
26 25 adantl x D log i x + 1 x 2
27 ovexd x D i 1 x 2 V
28 simpr x i x + 1 x 2 i x + 1 x 2
29 asinlem3 x 0 i x + 1 x 2
30 rere i x + 1 x 2 i x + 1 x 2 = i x + 1 x 2
31 30 breq2d i x + 1 x 2 0 i x + 1 x 2 0 i x + 1 x 2
32 31 biimpac 0 i x + 1 x 2 i x + 1 x 2 0 i x + 1 x 2
33 29 32 sylan x i x + 1 x 2 0 i x + 1 x 2
34 23 adantr x i x + 1 x 2 i x + 1 x 2 0
35 28 33 34 ne0gt0d x i x + 1 x 2 0 < i x + 1 x 2
36 0re 0
37 ltnle 0 i x + 1 x 2 0 < i x + 1 x 2 ¬ i x + 1 x 2 0
38 36 37 mpan i x + 1 x 2 0 < i x + 1 x 2 ¬ i x + 1 x 2 0
39 38 adantl x i x + 1 x 2 0 < i x + 1 x 2 ¬ i x + 1 x 2 0
40 35 39 mpbid x i x + 1 x 2 ¬ i x + 1 x 2 0
41 40 ex x i x + 1 x 2 ¬ i x + 1 x 2 0
42 12 41 syl x D i x + 1 x 2 ¬ i x + 1 x 2 0
43 imor i x + 1 x 2 ¬ i x + 1 x 2 0 ¬ i x + 1 x 2 ¬ i x + 1 x 2 0
44 42 43 sylib x D ¬ i x + 1 x 2 ¬ i x + 1 x 2 0
45 44 orcomd x D ¬ i x + 1 x 2 0 ¬ i x + 1 x 2
46 45 olcd x D ¬ −∞ < i x + 1 x 2 ¬ i x + 1 x 2 0 ¬ i x + 1 x 2
47 3ianor ¬ i x + 1 x 2 −∞ < i x + 1 x 2 i x + 1 x 2 0 ¬ i x + 1 x 2 ¬ −∞ < i x + 1 x 2 ¬ i x + 1 x 2 0
48 3orrot ¬ i x + 1 x 2 ¬ −∞ < i x + 1 x 2 ¬ i x + 1 x 2 0 ¬ −∞ < i x + 1 x 2 ¬ i x + 1 x 2 0 ¬ i x + 1 x 2
49 3orass ¬ −∞ < i x + 1 x 2 ¬ i x + 1 x 2 0 ¬ i x + 1 x 2 ¬ −∞ < i x + 1 x 2 ¬ i x + 1 x 2 0 ¬ i x + 1 x 2
50 47 48 49 3bitrri ¬ −∞ < i x + 1 x 2 ¬ i x + 1 x 2 0 ¬ i x + 1 x 2 ¬ i x + 1 x 2 −∞ < i x + 1 x 2 i x + 1 x 2 0
51 mnfxr −∞ *
52 elioc2 −∞ * 0 i x + 1 x 2 −∞ 0 i x + 1 x 2 −∞ < i x + 1 x 2 i x + 1 x 2 0
53 51 36 52 mp2an i x + 1 x 2 −∞ 0 i x + 1 x 2 −∞ < i x + 1 x 2 i x + 1 x 2 0
54 50 53 xchbinxr ¬ −∞ < i x + 1 x 2 ¬ i x + 1 x 2 0 ¬ i x + 1 x 2 ¬ i x + 1 x 2 −∞ 0
55 46 54 sylib x D ¬ i x + 1 x 2 −∞ 0
56 22 55 eldifd x D i x + 1 x 2 −∞ 0
57 56 adantl x D i x + 1 x 2 −∞ 0
58 ovexd x D i i x + 1 x 2 1 x 2 V
59 eldifi y −∞ 0 y
60 eldifn y −∞ 0 ¬ y −∞ 0
61 0xr 0 *
62 mnflt0 −∞ < 0
63 ubioc1 −∞ * 0 * −∞ < 0 0 −∞ 0
64 51 61 62 63 mp3an 0 −∞ 0
65 eleq1 y = 0 y −∞ 0 0 −∞ 0
66 64 65 mpbiri y = 0 y −∞ 0
67 66 necon3bi ¬ y −∞ 0 y 0
68 60 67 syl y −∞ 0 y 0
69 59 68 logcld y −∞ 0 log y
70 69 adantl y −∞ 0 log y
71 ovexd y −∞ 0 1 y V
72 13 a1i x D i
73 72 12 mulcld x D i x
74 73 adantl x D i x
75 13 a1i x D i
76 12 adantl x D x
77 1cnd x D 1
78 simpr x x
79 1cnd x 1
80 11 dvmptid dx x d x = x 1
81 5 a1i D
82 eqid TopOpen fld = TopOpen fld
83 82 cnfldtopon TopOpen fld TopOn
84 83 toponrestid TopOpen fld = TopOpen fld 𝑡
85 82 recld2 Clsd TopOpen fld
86 neg1rr 1
87 iocmnfcld 1 −∞ 1 Clsd topGen ran .
88 86 87 ax-mp −∞ 1 Clsd topGen ran .
89 1re 1
90 icopnfcld 1 1 +∞ Clsd topGen ran .
91 89 90 ax-mp 1 +∞ Clsd topGen ran .
92 uncld −∞ 1 Clsd topGen ran . 1 +∞ Clsd topGen ran . −∞ 1 1 +∞ Clsd topGen ran .
93 88 91 92 mp2an −∞ 1 1 +∞ Clsd topGen ran .
94 82 tgioo2 topGen ran . = TopOpen fld 𝑡
95 94 fveq2i Clsd topGen ran . = Clsd TopOpen fld 𝑡
96 93 95 eleqtri −∞ 1 1 +∞ Clsd TopOpen fld 𝑡
97 restcldr Clsd TopOpen fld −∞ 1 1 +∞ Clsd TopOpen fld 𝑡 −∞ 1 1 +∞ Clsd TopOpen fld
98 85 96 97 mp2an −∞ 1 1 +∞ Clsd TopOpen fld
99 83 toponunii = TopOpen fld
100 99 cldopn −∞ 1 1 +∞ Clsd TopOpen fld −∞ 1 1 +∞ TopOpen fld
101 98 100 ax-mp −∞ 1 1 +∞ TopOpen fld
102 1 101 eqeltri D TopOpen fld
103 102 a1i D TopOpen fld
104 11 78 79 80 81 84 82 103 dvmptres dx D x d x = x D 1
105 13 a1i i
106 11 76 77 104 105 dvmptcmul dx D i x d x = x D i 1
107 13 mulid1i i 1 = i
108 107 mpteq2i x D i 1 = x D i
109 106 108 eqtrdi dx D i x d x = x D i
110 12 sqcld x D x 2
111 16 110 18 sylancr x D 1 x 2
112 111 sqrtcld x D 1 x 2
113 112 adantl x D 1 x 2
114 ovexd x D x 1 x 2 V
115 elin x D x D x
116 1 asindmre D = 1 1
117 116 eqimssi D 1 1
118 117 sseli x D x 1 1
119 115 118 sylbir x D x x 1 1
120 incom 0 +∞ −∞ 0 = −∞ 0 0 +∞
121 pnfxr +∞ *
122 df-ioc . = x * , y * z * | x < z z y
123 df-ioo . = x * , y * z * | x < z z < y
124 xrltnle 0 * w * 0 < w ¬ w 0
125 122 123 124 ixxdisj −∞ * 0 * +∞ * −∞ 0 0 +∞ =
126 51 61 121 125 mp3an −∞ 0 0 +∞ =
127 120 126 eqtri 0 +∞ −∞ 0 =
128 elioore x 1 1 x
129 128 resqcld x 1 1 x 2
130 resubcl 1 x 2 1 x 2
131 89 129 130 sylancr x 1 1 1 x 2
132 86 rexri 1 *
133 1xr 1 *
134 elioo2 1 * 1 * x 1 1 x 1 < x x < 1
135 132 133 134 mp2an x 1 1 x 1 < x x < 1
136 recn x x
137 136 abscld x x
138 136 absge0d x 0 x
139 0le1 0 1
140 lt2sq x 0 x 1 0 1 x < 1 x 2 < 1 2
141 89 139 140 mpanr12 x 0 x x < 1 x 2 < 1 2
142 137 138 141 syl2anc x x < 1 x 2 < 1 2
143 abslt x 1 x < 1 1 < x x < 1
144 89 143 mpan2 x x < 1 1 < x x < 1
145 absresq x x 2 = x 2
146 sq1 1 2 = 1
147 146 a1i x 1 2 = 1
148 145 147 breq12d x x 2 < 1 2 x 2 < 1
149 resqcl x x 2
150 posdif x 2 1 x 2 < 1 0 < 1 x 2
151 149 89 150 sylancl x x 2 < 1 0 < 1 x 2
152 148 151 bitrd x x 2 < 1 2 0 < 1 x 2
153 142 144 152 3bitr3d x 1 < x x < 1 0 < 1 x 2
154 153 biimpd x 1 < x x < 1 0 < 1 x 2
155 154 3impib x 1 < x x < 1 0 < 1 x 2
156 135 155 sylbi x 1 1 0 < 1 x 2
157 131 156 elrpd x 1 1 1 x 2 +
158 ioorp 0 +∞ = +
159 157 158 eleqtrrdi x 1 1 1 x 2 0 +∞
160 disjel 0 +∞ −∞ 0 = 1 x 2 0 +∞ ¬ 1 x 2 −∞ 0
161 127 159 160 sylancr x 1 1 ¬ 1 x 2 −∞ 0
162 119 161 syl x D x ¬ 1 x 2 −∞ 0
163 elioc2 −∞ * 0 1 x 2 −∞ 0 1 x 2 −∞ < 1 x 2 1 x 2 0
164 51 36 163 mp2an 1 x 2 −∞ 0 1 x 2 −∞ < 1 x 2 1 x 2 0
165 164 biimpi 1 x 2 −∞ 0 1 x 2 −∞ < 1 x 2 1 x 2 0
166 165 simp1d 1 x 2 −∞ 0 1 x 2
167 resubcl 1 1 x 2 1 1 x 2
168 89 166 167 sylancr 1 x 2 −∞ 0 1 1 x 2
169 nncan 1 x 2 1 1 x 2 = x 2
170 16 169 mpan x 2 1 1 x 2 = x 2
171 170 eleq1d x 2 1 1 x 2 x 2
172 171 biimpa x 2 1 1 x 2 x 2
173 168 172 sylan2 x 2 1 x 2 −∞ 0 x 2
174 166 adantl x 2 1 x 2 −∞ 0 1 x 2
175 165 simp3d 1 x 2 −∞ 0 1 x 2 0
176 175 adantl x 2 1 x 2 −∞ 0 1 x 2 0
177 letr 1 x 2 0 1 1 x 2 0 0 1 1 x 2 1
178 36 89 177 mp3an23 1 x 2 1 x 2 0 0 1 1 x 2 1
179 139 178 mpan2i 1 x 2 1 x 2 0 1 x 2 1
180 174 176 179 sylc x 2 1 x 2 −∞ 0 1 x 2 1
181 subge0 1 1 x 2 0 1 1 x 2 1 x 2 1
182 89 174 181 sylancr x 2 1 x 2 −∞ 0 0 1 1 x 2 1 x 2 1
183 180 182 mpbird x 2 1 x 2 −∞ 0 0 1 1 x 2
184 170 adantr x 2 1 x 2 −∞ 0 1 1 x 2 = x 2
185 183 184 breqtrd x 2 1 x 2 −∞ 0 0 x 2
186 173 185 resqrtcld x 2 1 x 2 −∞ 0 x 2
187 17 186 sylan x 1 x 2 −∞ 0 x 2
188 eleq1 x = x 2 x x 2
189 187 188 syl5ibrcom x 1 x 2 −∞ 0 x = x 2 x
190 187 renegcld x 1 x 2 −∞ 0 x 2
191 eleq1 x = x 2 x x 2
192 190 191 syl5ibrcom x 1 x 2 −∞ 0 x = x 2 x
193 eqid x 2 = x 2
194 eqsqrtor x x 2 x 2 = x 2 x = x 2 x = x 2
195 17 194 mpdan x x 2 = x 2 x = x 2 x = x 2
196 193 195 mpbii x x = x 2 x = x 2
197 196 adantr x 1 x 2 −∞ 0 x = x 2 x = x 2
198 189 192 197 mpjaod x 1 x 2 −∞ 0 x
199 198 stoic1a x ¬ x ¬ 1 x 2 −∞ 0
200 12 199 sylan x D ¬ x ¬ 1 x 2 −∞ 0
201 162 200 pm2.61dan x D ¬ 1 x 2 −∞ 0
202 111 201 eldifd x D 1 x 2 −∞ 0
203 202 adantl x D 1 x 2 −∞ 0
204 2cnd x 2
205 id x x
206 204 205 mulcld x 2 x
207 206 negcld x 2 x
208 207 adantl x 2 x
209 12 208 sylan2 x D 2 x
210 59 sqrtcld y −∞ 0 y
211 210 adantl y −∞ 0 y
212 ovexd y −∞ 0 1 2 y V
213 19 adantl x 1 x 2
214 36 a1i x 0
215 1cnd 1
216 11 215 dvmptc dx 1 d x = x 0
217 17 adantl x x 2
218 2cn 2
219 mulcl 2 x 2 x
220 218 219 mpan x 2 x
221 220 adantl x 2 x
222 2nn 2
223 dvexp 2 dx x 2 d x = x 2 x 2 1
224 222 223 ax-mp dx x 2 d x = x 2 x 2 1
225 2m1e1 2 1 = 1
226 225 oveq2i x 2 1 = x 1
227 exp1 x x 1 = x
228 226 227 eqtrid x x 2 1 = x
229 228 oveq2d x 2 x 2 1 = 2 x
230 229 mpteq2ia x 2 x 2 1 = x 2 x
231 224 230 eqtri dx x 2 d x = x 2 x
232 231 a1i dx x 2 d x = x 2 x
233 11 79 214 216 217 221 232 dvmptsub dx 1 x 2 d x = x 0 2 x
234 df-neg 2 x = 0 2 x
235 234 mpteq2i x 2 x = x 0 2 x
236 233 235 eqtr4di dx 1 x 2 d x = x 2 x
237 11 213 208 236 81 84 82 103 dvmptres dx D 1 x 2 d x = x D 2 x
238 eqid −∞ 0 = −∞ 0
239 238 dvcnsqrt dy −∞ 0 y d y = y −∞ 0 1 2 y
240 239 a1i dy −∞ 0 y d y = y −∞ 0 1 2 y
241 fveq2 y = 1 x 2 y = 1 x 2
242 241 oveq2d y = 1 x 2 2 y = 2 1 x 2
243 242 oveq2d y = 1 x 2 1 2 y = 1 2 1 x 2
244 11 11 203 209 211 212 237 240 241 243 dvmptco dx D 1 x 2 d x = x D 1 2 1 x 2 2 x
245 mulneg2 2 x 2 x = 2 x
246 218 12 245 sylancr x D 2 x = 2 x
247 246 oveq1d x D 2 x 2 1 x 2 = 2 x 2 1 x 2
248 12 negcld x D x
249 eldifn x −∞ 1 1 +∞ ¬ x −∞ 1 1 +∞
250 249 1 eleq2s x D ¬ x −∞ 1 1 +∞
251 id x = 1 x = 1
252 mnflt 1 −∞ < 1
253 86 252 ax-mp −∞ < 1
254 ubioc1 −∞ * 1 * −∞ < 1 1 −∞ 1
255 51 132 253 254 mp3an 1 −∞ 1
256 251 255 eqeltrdi x = 1 x −∞ 1
257 id x = 1 x = 1
258 ltpnf 1 1 < +∞
259 89 258 ax-mp 1 < +∞
260 lbico1 1 * +∞ * 1 < +∞ 1 1 +∞
261 133 121 259 260 mp3an 1 1 +∞
262 257 261 eqeltrdi x = 1 x 1 +∞
263 256 262 orim12i x = 1 x = 1 x −∞ 1 x 1 +∞
264 263 orcoms x = 1 x = 1 x −∞ 1 x 1 +∞
265 elun x −∞ 1 1 +∞ x −∞ 1 x 1 +∞
266 264 265 sylibr x = 1 x = 1 x −∞ 1 1 +∞
267 250 266 nsyl x D ¬ x = 1 x = 1
268 1cnd x 1 x 2 = 0 1
269 17 adantr x 1 x 2 = 0 x 2
270 19 adantr x 1 x 2 = 0 1 x 2
271 simpr x 1 x 2 = 0 1 x 2 = 0
272 270 271 sqr00d x 1 x 2 = 0 1 x 2 = 0
273 268 269 272 subeq0d x 1 x 2 = 0 1 = x 2
274 146 273 eqtr2id x 1 x 2 = 0 x 2 = 1 2
275 274 ex x 1 x 2 = 0 x 2 = 1 2
276 sqeqor x 1 x 2 = 1 2 x = 1 x = 1
277 16 276 mpan2 x x 2 = 1 2 x = 1 x = 1
278 275 277 sylibd x 1 x 2 = 0 x = 1 x = 1
279 278 necon3bd x ¬ x = 1 x = 1 1 x 2 0
280 12 267 279 sylc x D 1 x 2 0
281 2cnne0 2 2 0
282 divcan5 x 1 x 2 1 x 2 0 2 2 0 2 x 2 1 x 2 = x 1 x 2
283 281 282 mp3an3 x 1 x 2 1 x 2 0 2 x 2 1 x 2 = x 1 x 2
284 248 112 280 283 syl12anc x D 2 x 2 1 x 2 = x 1 x 2
285 218 12 219 sylancr x D 2 x
286 285 negcld x D 2 x
287 mulcl 2 1 x 2 2 1 x 2
288 218 112 287 sylancr x D 2 1 x 2
289 mulne0 2 2 0 1 x 2 1 x 2 0 2 1 x 2 0
290 281 289 mpan 1 x 2 1 x 2 0 2 1 x 2 0
291 112 280 290 syl2anc x D 2 1 x 2 0
292 286 288 291 divrec2d x D 2 x 2 1 x 2 = 1 2 1 x 2 2 x
293 247 284 292 3eqtr3rd x D 1 2 1 x 2 2 x = x 1 x 2
294 293 mpteq2ia x D 1 2 1 x 2 2 x = x D x 1 x 2
295 244 294 eqtrdi dx D 1 x 2 d x = x D x 1 x 2
296 11 74 75 109 113 114 295 dvmptadd dx D i x + 1 x 2 d x = x D i + x 1 x 2
297 mulcl i 1 x 2 i 1 x 2
298 13 20 297 sylancr x i 1 x 2
299 12 298 syl x D i 1 x 2
300 299 248 112 280 divdird x D i 1 x 2 + x 1 x 2 = i 1 x 2 1 x 2 + x 1 x 2
301 ixi i i = 1
302 301 eqcomi 1 = i i
303 302 oveq1i -1 x = i i x
304 mulm1 x -1 x = x
305 mulass i i x i i x = i i x
306 13 13 305 mp3an12 x i i x = i i x
307 303 304 306 3eqtr3a x x = i i x
308 307 oveq1d x - x + i 1 x 2 = i i x + i 1 x 2
309 negcl x x
310 298 309 addcomd x i 1 x 2 + x = - x + i 1 x 2
311 13 a1i x i
312 311 15 20 adddid x i i x + 1 x 2 = i i x + i 1 x 2
313 308 310 312 3eqtr4d x i 1 x 2 + x = i i x + 1 x 2
314 12 313 syl x D i 1 x 2 + x = i i x + 1 x 2
315 314 oveq1d x D i 1 x 2 + x 1 x 2 = i i x + 1 x 2 1 x 2
316 72 112 280 divcan4d x D i 1 x 2 1 x 2 = i
317 316 oveq1d x D i 1 x 2 1 x 2 + x 1 x 2 = i + x 1 x 2
318 300 315 317 3eqtr3rd x D i + x 1 x 2 = i i x + 1 x 2 1 x 2
319 318 mpteq2ia x D i + x 1 x 2 = x D i i x + 1 x 2 1 x 2
320 296 319 eqtrdi dx D i x + 1 x 2 d x = x D i i x + 1 x 2 1 x 2
321 logf1o log : 0 1-1 onto ran log
322 f1of log : 0 1-1 onto ran log log : 0 ran log
323 321 322 mp1i log : 0 ran log
324 snssi 0 −∞ 0 0 −∞ 0
325 64 324 ax-mp 0 −∞ 0
326 sscon 0 −∞ 0 −∞ 0 0
327 325 326 mp1i −∞ 0 0
328 323 327 feqresmpt log −∞ 0 = y −∞ 0 log y
329 328 oveq2d D log −∞ 0 = dy −∞ 0 log y d y
330 238 dvlog D log −∞ 0 = y −∞ 0 1 y
331 329 330 eqtr3di dy −∞ 0 log y d y = y −∞ 0 1 y
332 fveq2 y = i x + 1 x 2 log y = log i x + 1 x 2
333 oveq2 y = i x + 1 x 2 1 y = 1 i x + 1 x 2
334 11 11 57 58 70 71 320 331 332 333 dvmptco dx D log i x + 1 x 2 d x = x D 1 i x + 1 x 2 i i x + 1 x 2 1 x 2
335 22 24 reccld x D 1 i x + 1 x 2
336 mulcl i i x + 1 x 2 i i x + 1 x 2
337 13 21 336 sylancr x i i x + 1 x 2
338 12 337 syl x D i i x + 1 x 2
339 335 338 112 280 divassd x D 1 i x + 1 x 2 i i x + 1 x 2 1 x 2 = 1 i x + 1 x 2 i i x + 1 x 2 1 x 2
340 338 22 24 divrec2d x D i i x + 1 x 2 i x + 1 x 2 = 1 i x + 1 x 2 i i x + 1 x 2
341 72 22 24 divcan4d x D i i x + 1 x 2 i x + 1 x 2 = i
342 340 341 eqtr3d x D 1 i x + 1 x 2 i i x + 1 x 2 = i
343 342 oveq1d x D 1 i x + 1 x 2 i i x + 1 x 2 1 x 2 = i 1 x 2
344 339 343 eqtr3d x D 1 i x + 1 x 2 i i x + 1 x 2 1 x 2 = i 1 x 2
345 344 mpteq2ia x D 1 i x + 1 x 2 i i x + 1 x 2 1 x 2 = x D i 1 x 2
346 334 345 eqtrdi dx D log i x + 1 x 2 d x = x D i 1 x 2
347 negicn i
348 347 a1i i
349 11 26 27 346 348 dvmptcmul dx D i log i x + 1 x 2 d x = x D i i 1 x 2
350 349 mptru dx D i log i x + 1 x 2 d x = x D i i 1 x 2
351 divass i i 1 x 2 1 x 2 0 i i 1 x 2 = i i 1 x 2
352 347 13 351 mp3an12 1 x 2 1 x 2 0 i i 1 x 2 = i i 1 x 2
353 112 280 352 syl2anc x D i i 1 x 2 = i i 1 x 2
354 13 13 mulneg1i i i = i i
355 301 negeqi i i = -1
356 negneg1e1 -1 = 1
357 354 355 356 3eqtri i i = 1
358 357 oveq1i i i 1 x 2 = 1 1 x 2
359 353 358 eqtr3di x D i i 1 x 2 = 1 1 x 2
360 359 mpteq2ia x D i i 1 x 2 = x D 1 1 x 2
361 9 350 360 3eqtri D arcsin D = x D 1 1 x 2