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
