>> syms a s t a1 f R t
>> t=solve('(a-2*a*s*t)^2+(b+(sin(a1)+4*f*s)*t-f)^2=R^2',t)
t =
((4*R^2*a^2*s^2 + 16*R^2*f^2*s^2 + 8*R^2*f*s*sin(a1) + R^2*sin(a1)^2 - 4*a^2*b^2*s^2 - 8*a^2*b*f*s^2 - 4*a^2*b*s*sin(a1) - 4*a^2*f^2*s^2 - 4*a^2*f*s*sin(a1) - a^2*sin(a1)^2)^(1/2) + 2*a^2*s - b*sin(a1) + 4*f^2*s + f*sin(a1) - 4*b*f*s)/(4*a^2*s^2 + 16*f^2*s^2 + 8*f*s*sin(a1) + sin(a1)^2)
-((4*R^2*a^2*s^2 + 16*R^2*f^2*s^2 + 8*R^2*f*s*sin(a1) + R^2*sin(a1)^2 - 4*a^2*b^2*s^2 - 8*a^2*b*f*s^2 - 4*a^2*b*s*sin(a1) - 4*a^2*f^2*s^2 - 4*a^2*f*s*sin(a1) - a^2*sin(a1)^2)^(1/2) - 2*a^2*s + b*sin(a1) - 4*f^2*s - f*sin(a1) + 4*b*f*s)/(4*a^2*s^2 + 16*f^2*s^2 + 8*f*s*sin(a1) + sin(a1)^2)
是的 t用其他字母代替,有数字的时候不是这样算得么。