How can I specify a parameter to solve a system of equations symbolically?

I have defined a variable for time (t), velocity (v) and postion (p):

syms v_0 t_1 v_1 p_1

Now a define a system of equations to calculate the position and speed at time t_1 depending on the initial speed v_0:

eqns_1 = [ ...
    t_1 == 1.0, ...
    v_1 == v_0, ...
    p_1 == v_0 * t_1, ...
]

As a result I would expect:

struct with fields:

t_1: 2
v_1: v_0
p_1: 2*v_0

I tried

solution_1 = solve(eqns_1)

and

solution_2 = solve(eqns_1,'ReturnConditions',true)

which both deliver

struct with fields:

t_1: 1
v_0: p_1
v_1: p_1

So how can I specify that v_0 is my parameter and not p_1?

Answer 1

[Torsten]

syms v_0 t_1 v_1 p_1
eqns_1 = [ ...
    t_1 == 2.0, ...
    v_1 == v_0, ...
    p_1 == v_0 * t_1, ...
    ];
solve(eqns_1,[t_1,v_1,p_1])

ans = struct with fields:
    t_1: 2
    v_1: v_0
    p_1: 2*v_0

[Karsten Gordon]

Works like a charm. Thank you for your quick support Torsten!