逼近函数
function f = Legendre(y,k,x0)syms t;
P(1:k+1) = t;
P(1) = 1;
P(2) = t;
c(1:k+1) = 0.0;
c(1)=int(subs(y,findsym(sym(y)),sym('t'))*P(1),t,-1,1)/2;
c(2)=int(subs(y,findsym(sym(y)),sym('t'))*P(2),t,-1,1)/2;
f = c(1)+c(2)*t;
for i=3:k+1
P(i) = ((2*i-3)*P(i-1)*t-(i-2)*P(i-2))/(i-1);
c(i) = int(subs(y,findsym(sym(y)),t)*P(i),t,-1,1)/2;
f = f + c(i)*P(i);
if(i==k+1)
if(nargin == 3)
f = subs(f,'t',x0);
else
f = vpa(f,6);
end
end
end ????? 顶顶顶顶顶顶顶顶顶顶顶顶的 lihan厉害厉害厉害厉害厉害 好 dwadedcsargtg 这是什么哦? 呵呵,非常感谢,很好很强大
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