其它物理量的涨落和关联 f=f({X}) 于=f(x)=f({) △f=f({X)-f=f({X1+△X})-f =∑（影）Ax =∑（影）∑(Am=E(x)Am =(A ag=∑(x)A=∑()A其它物理量的涨落和关联 𝑓 = 𝑓 ({𝑋𝑙}) 𝑓 = 𝑓 ({𝑋𝑙}) = 𝑓 ({𝑦𝑙}) Δ 𝑓 = 𝑓 ({𝑋𝑙}) − 𝑓 = 𝑓 ({𝑋𝑙 + Δ𝑋𝑙}) − 𝑓 = Õ 𝑙  𝜕 𝑓 𝜕𝑋𝑙  Δ𝑋𝑙 = Õ 𝑙  𝜕 𝑓 𝜕𝑋𝑙  Õ 𝑚  𝜕𝑋𝑙 𝜕𝑦𝑚  Δ𝑦𝑚 = Õ 𝑚 hÕ 𝑙  𝜕 𝑓 𝜕𝑋𝑙   𝜕𝑋𝑙 𝜕𝑦𝑚  iΔ𝑦𝑚 = Õ 𝑚  𝜕 𝑓 𝜕𝑦𝑚  Δ𝑦𝑚 Δ𝑔 = Õ 𝑙  𝜕𝑔 𝜕𝑋𝑙  Δ𝑋𝑙 = Õ 𝑚  𝜕𝑔 𝜕𝑦𝑚  Δ𝑦𝑚