Question solve(eqn)

22 次查看（过去 30 天）
Jothi
Jothi 2025-2-24
编辑： Walter Roberson 2025-2-24
Hello, I'm wondering, how can we take the values of the different variables which where found by the function 'solve' and use them for another calculation ? I wrote this and i need the values of a0, a1, a2, a3, a4 and a5 for the calculation of f7.
syms a0 a1 a2 a3 a4 a5
v = [0 2 4 6 8 10]
f = [0 2.9 14.8 39.6 74.3 119]
f1 = a0 + a1*v(1) + a2*v(1)^2 + a3*v(1)^3 + a4*v(1)^4 + a5*v(1)^5 == 0
f2 = a0 + a1*v(2) + a2*v(2)^2 + a3*v(2)^3 + a4*v(2)^4 + a5*v(2)^5 == 2.9
f3 = a0 + a1*v(3) + a2*v(3)^2 + a3*v(3)^3 + a4*v(3)^4 + a5*v(3)^5 == 14.8
f4 = a0 + a1*v(4) + a2*v(4)^2 + a3*v(4)^3 + a4*v(4)^4 + a5*v(4)^5 == 39.6
f5 = a0 + a1*v(5) + a2*v(5)^2 + a3*v(5)^3 + a4*v(5)^4 + a5*v(5)^5 == 74.3
f6 = a0 + a1*v(6) + a2*v(6)^2 + a3*v(6)^3 + a4*v(6)^4 + a5*v(6)^5 == 119
solve (f1, f2, f3, f4, f5, f6)
% Lorsque le projectile se déplace à la vitesse de 750 ft/sec, la force de
% ce même projectile est :
v(7) = 750;
% Calcul de la force
f7 = a0 + a1*v(7) + a2*v(7)^2 + a3*v(7)^3 + a4*v(7)^4 + a5*v(7)^5

请先登录，再回答此问题。

回答（2 个）

Torsten
Torsten 2025-2-24
编辑：Torsten 2025-2-24
Replace
solve (f1, f2, f3, f4, f5, f6)
by
[a0,a1,a2,a3,a4,a5] = solve (f1, f2, f3, f4, f5, f6)
But note that extrapolating the function from the interval [0 10] for v to v = 750 is doubtful.
Walter Roberson
Walter Roberson 2025-2-24
编辑：Walter Roberson 2025-2-24
Ran in:
syms a0 a1 a2 a3 a4 a5
v = [0 2 4 6 8 10]
v = 1×6
0 2 4 6 8 10
<mw-icon class=""></mw-icon>
<mw-icon class=""></mw-icon>
f = [0 2.9 14.8 39.6 74.3 119]
f = 1×6
0 2.9000 14.8000 39.6000 74.3000 119.0000
<mw-icon class=""></mw-icon>
<mw-icon class=""></mw-icon>
f1 = a0 + a1*v(1) + a2*v(1)^2 + a3*v(1)^3 + a4*v(1)^4 + a5*v(1)^5 == f(1)
f1 = 
f2 = a0 + a1*v(2) + a2*v(2)^2 + a3*v(2)^3 + a4*v(2)^4 + a5*v(2)^5 == f(2)
f2 = 
f3 = a0 + a1*v(3) + a2*v(3)^2 + a3*v(3)^3 + a4*v(3)^4 + a5*v(3)^5 == f(3)
f3 = 
f4 = a0 + a1*v(4) + a2*v(4)^2 + a3*v(4)^3 + a4*v(4)^4 + a5*v(4)^5 == f(4)
f4 = 
f5 = a0 + a1*v(5) + a2*v(5)^2 + a3*v(5)^3 + a4*v(5)^4 + a5*v(5)^5 == f(5)
f5 = 
f6 = a0 + a1*v(6) + a2*v(6)^2 + a3*v(6)^3 + a4*v(6)^4 + a5*v(6)^5 == f(6)
f6 = 
sol = solve([f1, f2, f3, f4, f5, f6])
sol = struct with fields:
a0: 0 a1: 137/80 a2: -1147/960 a3: 127/192 a4: -269/3840 a5: 1/384
% Lorsque le projectile se déplace à la vitesse de 750 ft/sec, la force de
% ce même projectile est :
v(7) = 750;
% Calcul de la force
f7 = subs(a0 + a1*v(7) + a2*v(7)^2 + a3*v(7)^3 + a4*v(7)^4 + a5*v(7)^5, sol)
f7 = 

类别

在 Help Center 和 File Exchange 中查找有关 Numeric Solvers 的更多信息

标签

产品


版本

R2024a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by