search for: invroot2pi

...arison (so I cannot be 100% sure of my algebra). What I would like is for the output of D to look at least somewhat similar to my hand algebra. It occurred to me that if expressions could be constructed from subexpressions, I could get a more readable result (from D), as opposed to > fx2 -(invroot2pi/sigma) * (exp(-0.5 * (((x - mu)/sigma)^2)) * (0.5 * (2 * (1/sigma * (1/sigma)))) - exp(-0.5 * (((x - mu)/sigma)^2)) * (0.5 * (2 * (1/sigma * ((x - mu)/sigma)))) * (0.5 * (2 * (1/sigma * ((x - mu)/sigma))))) So I tried, in the interests of simplification.. > expr1<-expression...