solve equation for variable and how to get output as number not as substituted form

Hi, I tried solving following code.solved for t and i want to substitutethat value back into equation. please help me

x1=rand(1); y1=rand(1); r = 10; v1= 2*rand(1); v2= 2*rand(1); sym t eq=(x1+t*v1)^2+(y1+t*v1)^2-r^2

solt=solve(eq,t); subsv=subs(eq,{t},{solt})

Thanks, Sita

Answer 1

[A Jenkins]

x1=rand(1); 
y1=rand(1); 
r = 10; 
v1= 2*rand(1); 
v2= 2*rand(1); 
syms t 
eq=(x1+t*v1)^2+(y1+t*v1)^2-r^2;
solt=solve(eq,t); 
subsv=subs(eq,{t},{solt});

>> help vpa
 vpa    Variable precision arithmetic.
    R = vpa(S) numerically evaluates each element of the double matrix
    S using variable precision floating point arithmetic with D decimal
    digit accuracy, where D is the current setting of DIGITS 

>> vpa(subsv)

ans =

   0
   0

[sita]

Thank you