I have a question about an expression that I want to modify. Here is the expression:
-(((cA - 2 cF) (-cF (1 + x) log[1 - x] + cF (-(1/3) π^2 delta[1 - x] + plusd[(2 Log[1 - x])/(1 - x)])))/(2 cF)) + 1/2 cA (delta[ 1 - x] (1/2 (-3 + mgl^2/(mgl^2 + sa1)) + (mgl^2 Log[mgl^2/(mgl^2 + sa1)])/ sa1) + (3/2 cF delta[ 1 - x] ((2 mgl)/(mgl + Sqrt[mgl^2 + sa1]) + Log[(2 mgl^2 + sa1 - 2 mgl Sqrt[mgl^2 + sa1])/sa1]) - cF (1 + x) Log[(sa1 (1 - x))/(mgl^2 + sa1 (1 - x))])/ cF + (2 Log[2 - x])/(-1 + x) + 2 Log[(sa1 (-2 + x))/(-mgl^2 + sa1 (-2 + x))] plusd[1/(1 - x)] + Log[2 + mgl^2/sa1 - x] plusd[-(2/(-1 + x))] + 2 plusd[Log[1 - x]/(1 - x)] + plusd[-((sa1^2 (-1 + x))/(2 (mgl^2 + sa1 - sa1 x)^2)) + (2 (1 + Log[1 + mgl^2/sa1 - x]))/(-1 + x)]) + 1/2 (cA - 2 cF) (-cF (5 - π^2) delta[1 - x] + cF (1 - x - (1 + x) Log[(1 - x)/x] + plusd[(2 Log[(1 - x)/x])/(1 - x)]))
hm, looks a bit weird but I am new to this forum and don't know how to format that expression in a proper way :D.
So, now I want to collect some terms. I have a function, called
plusd. The function has different arguments including
x and the function is multiplied by a sequence of other expressions.
What I want is to replace
1 in each factor that is multiplied by that function, not in the function argument itself and not in the part not multiplied by the function. The other part, which is not multiplied by that function I want to set to zero.
I guess it is easy with some pattern matching stuff but my skills are not good enough so I am asking here for help.
I am glad for any advice and of course also how to post my formulas in a nicer way.
Cheers and best regards,