@@ -41,49 +41,29 @@ This test problem is about the optimal-time launching of a satellite into orbit
4141Given by
4242
4343```math
44- \f rac{dz_1}{dt}=z_3t_f
45- ```
46- ```math
47- \f rac{dz_2}{dt}=z_4t_f
48- ```
49- ```math
50- \f rac{dz_3}{dt}=A\c os(z_5)t_f
51- ```
52- ```math
53- \f rac{dz_4}{dt}=(A\s in(z_5)-g)t_f
54- ```
55- ```math
56- \f rac{dz_5}{dt}=-z_6\c os(z_5)t_F
57- ```
58- ```math
59- \f rac{dz_6}{dt}=z_6^2\s in(z_5)t_f
60- ```
61- ```math
62- \f rac{dz_7}{dt}=0
44+ \b egin{align*}
45+ \f rac{dz_1}{dt} &= z_3 t_f, &
46+ \f rac{dz_2}{dt} &= z_4 t_f, \\
47+ \f rac{dz_3}{dt} &= A\c os(z_5) t_f, &
48+ \f rac{dz_4}{dt} &= (A\s in(z_5)-g) t_f, \\
49+ \f rac{dz_5}{dt} &= -z_6\c os(z_5) t_F, &
50+ \f rac{dz_6}{dt} &= z_6^2\s in(z_5) t_f, \\
51+ \f rac{dz_7}{dt} &= 0,
52+ \e nd{align*}
6353```
6454
6555with boundary condition
6656
6757```math
68- z_1(0)=0
69- ```
70- ```math
71- z_2(0)=0
72- ```
73- ```math
74- z_3(0)=0
75- ```
76- ```math
77- z_4(0)=0
78- ```
79- ```math
80- z_5(1)=h
81- ```
82- ```math
83- z_6(1)=V_c
84- ```
85- ```math
86- z_7(1)=0
58+ \b egin{align*}
59+ z_1(0) &= 0, &
60+ z_2(0) &= 0, \\
61+ z_3(0) &= 0, &
62+ z_4(0) &= 0, \\
63+ z_5(1) &= h, &
64+ z_6(1) &= V_c, \\
65+ z_7(1) &= 0.
66+ \e nd{align*}
8767```
8868
8969# Solution
@@ -134,49 +114,29 @@ Launch of a satellite into circular orbit from a flat Earth where we assume a un
134114Given by
135115
136116```math
137- \f rac{dz_1}{dt}=z_3\f rac{V_c}{h}
138- ```
139- ```math
140- \f rac{dz_2}{dt}=z_4\f rac{V_c}{h}
141- ```
142- ```math
143- \f rac{dz_3}{dt}=acc\f rac{1}{|V_c|\s qrt{1+z_6^2}}
144- ```
145- ```math
146- \f rac{dz_4}{dt}=acc\f rac{1}{|V_c|\s qrt{1+z_6^2}}-\f rac{g}{V_c}
147- ```
148- ```math
149- \f rac{dz_5}{dt}=0
150- ```
151- ```math
152- \f rac{dz_6}{dt}=-z_5\f rac{V_c}{h}
153- ```
154- ```math
155- \f rac{dz_7}{dt}=0
117+ \b egin{align*}
118+ \f rac{dz_1}{dt} &= z_3 \f rac{V_c}{h}, \\ [2pt]
119+ \f rac{dz_2}{dt} &= z_4 \f rac{V_c}{h}, \\ [2pt]
120+ \f rac{dz_3}{dt} &= acc \f rac{1}{|V_c|\s qrt{1+z_6^2}}, \\ [2pt]
121+ \f rac{dz_4}{dt} &= acc \f rac{1}{|V_c|\s qrt{1+z_6^2}}-\f rac{g}{V_c}, \\ [2pt]
122+ \f rac{dz_5}{dt} &= 0, \\ [2pt]
123+ \f rac{dz_6}{dt} &= -z_5 \f rac{V_c}{h}, \\ [2pt]
124+ \f rac{dz_7}{dt} &= 0,
125+ \e nd{align*}
156126```
157127
158- with boundary condition
128+ with boundary conditions
159129
160130```math
161- z_1(0)=0
162- ```
163- ```math
164- z_2(0)=0
165- ```
166- ```math
167- z_3(0)=0
168- ```
169- ```math
170- z_4(0)=0
171- ```
172- ```math
173- z_5(1)=h
174- ```
175- ```math
176- z_6(1)=V_c
177- ```
178- ```math
179- z_7(1)=0
131+ \b egin{align*}
132+ z_1(0) &= 0, &
133+ z_2(0) &= 0, \\
134+ z_3(0) &= 0, &
135+ z_4(0) &= 0, \\
136+ z_5(1) &= h, &
137+ z_6(1) &= V_c, \\
138+ z_7(1) &= 0.
139+ \e nd{align*}
180140```
181141
182142# Solution
@@ -261,49 +221,29 @@ Launch into circular orbit from a flat Earth including athmosferic drag.
261221Given by
262222
263223```math
264- \f rac{dz_1}{dt}=z_3\f rac{V_c}{h}
265- ```
266- ```math
267- \f rac{dz_2}{dt}=z_4\f rac{V_c}{h}
268- ```
269- ```math
270- \f rac{dz_3}{dt}=\f rac{f}{V_c}(-\f rac{z_6}{z_6^2+z_7^2}-V_c\e ta\e xp(-z_2\b eta)z_3\s qrt{z_3^3+z_4^2})/m
271- ```
272- ```math
273- \f rac{dz_4}{dt}=\f rac{f}{V_c}(-\f rac{z_7}{z_6^2+z_7^2}-V_c\e ta\e xp(-z_2\b eta)z_4\s qrt{z_3^3+z_4^2})/m - g_{accel}/V_c
274- ```
275- ```math
276- \f rac{dz_5}{dt}=-\e ta\b eta\e xp(-z_2\b eta)(z_6z_3+z_7z_4)\s qrt{z_3^3+z_4^2}\f rac{V_c}{m}
277- ```
278- ```math
279- \f rac{dz_6}{dt}=\e ta\e xp(-z_2\b eta)(z_6(2z_3^2+z_4^2)+z_7z_3z_4)V_c/\s qrt{z_3^2+z_4^2}/m
280- ```
281- ```math
282- \f rac{dz_7}{dt}=\e ta\e xp(-z_2\b eta)(z_7(z_3^2+2z_4^2)+z_6z_3z_4)V_c/\s qrt{z_3^2+z_4^2}/m
224+ \b egin{align*}
225+ \f rac{dz_1}{dt} &= z_3 \f rac{V_c}{h} \\
226+ \f rac{dz_2}{dt} &= z_4 \f rac{V_c}{h} \\
227+ \f rac{dz_3}{dt} &= \f rac{f}{V_c} \l eft(-\f rac{z_6}{z_6^2+z_7^2} - V_c η\e xp(-z_2 β) z_3\s qrt{z_3^3+z_4^2}\r ight)/m \\
228+ \f rac{dz_4}{dt} &= \f rac{f}{V_c} \l eft(-\f rac{z_7}{z_6^2+z_7^2} - V_c η\e xp(-z_2 β) z_4\s qrt{z_3^3+z_4^2}\r ight)/m - g_{accel}/V_c \\
229+ \f rac{dz_5}{dt} &= -ηβ \e xp(-z_2 β) (z_6z_3+z_7z_4)\s qrt{z_3^3+z_4^2}\f rac{V_c}{m} \\
230+ \f rac{dz_6}{dt} &= η \e xp(-z_2 β) \l eft(z_6(2z_3^2+z_4^2)+z_7z_3z_4\r ight) V_c/\s qrt{z_3^2+z_4^2}/m \\
231+ \f rac{dz_7}{dt} &= η \e xp(-z_2 β) \l eft(z_7(z_3^2+2z_4^2)+z_6z_3z_4\r ight) V_c/\s qrt{z_3^2+z_4^2}/m \\
232+ \e nd{align*}
283233```
284234
285- with boundary condition
235+ with boundary conditions
286236
287237```math
288- z_1(0)=0
289- ```
290- ```math
291- z_2(0)=0
292- ```
293- ```math
294- z_3(0)=0
295- ```
296- ```math
297- z_4(0)=0
298- ```
299- ```math
300- z_5(1)=h
301- ```
302- ```math
303- z_6(1)=V_c
304- ```
305- ```math
306- z_7(1)=0
238+ \b egin{align*}
239+ z_1(0) &= 0, &
240+ z_2(0) &= 0, \\
241+ z_3(0) &= 0, &
242+ z_4(0) &= 0, \\
243+ z_5(1) &= h, &
244+ z_6(1) &= V_c, \\
245+ z_7(1) &= 0.
246+ \e nd{align*}
307247```
308248
309249# Solution
@@ -346,22 +286,19 @@ This is an epidemiology model, about the spread of diseases.
346286Given by
347287
348288```math
349- \f rac{dy_1}{dt}=\m u-\b eta(t)y_1y_3
350- ```
351- ```math
352- \f rac{dy_2}{dt}=\b eta(t)y_1y_3-y_2/\l ambda
353- ```
354- ```math
355- \f rac{dy_3}{dt}=y_2/\l ambda-y_3/\e ta
289+ \b egin{align*}
290+ \f rac{dy_1}{dt} &= μ - β(t) y_1 y_3 \\
291+ \f rac{dy_2}{dt} &= β(t) y_1 y_3 - \f rac{y_2}{λ} \\
292+ \f rac{dy_3}{dt} &= \f rac{y_2}{λ} - \f rac{y_3}{η}
293+ \e nd{align*}
356294```
357295
358296with boundary condition
359297
360298```math
361- y(0)= y(1)
299+ y(0) = y(1)
362300```
363301
364-
365302# Solution
366303
367304No analytical solution
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