在MATLAB中这个式子f=(x-90)(1/(sqrt(2*pi)*0.3))*exp^(-((x-L)^2/(2*0

syms x L
>> f=(x-90)*(1/(sqrt(2*pi)*0.3))*exp(-((x-L)^2/(2*0.18)))
f =
(5988921017860761/4503599627370496*x-269501445803734245/2251799813685248)*exp(-25/9*(x-L)^2)
所以应该是：
f=(x-90)*(1/(sqrt(2*pi)*0.3))*exp(-((x-L)^2/(2*0.18)))