[R] multiply of two expressions

 hello, i want to differentiate of L with respect to b when: L= k*ln (k/(k+mu)) + sum(y) * ln (1-(k/mu+k))   #(negative binomial ln likelihood) and ln(mu/(mu+k)) = a+bx   #link function how can i do it in R? thank you. _ Best Regards Niloofar.Javanrouh Ph.D Student of

[R] help

  Hi dear all I want to analysis of covariance with R software. What should I do? I would like to have the answer as soon as possible because I have a presentation in the following 8 hours. Thanks a universe. _ Best Regards [[alternative HTML version deleted]] __