Question

Hi Can any expert help by defining Jacobian of a matrix and making Jacobian of the following equations.
P=c(u+g+d)/(b^2+(u+d)(u+g+d))
>L=(b/u+g+d)^2.P
>S=(g/(j+u+d))[b/(u+g+d)]^2.P
>Q=(gj/(u+d)(j+u+d))[(b/(u+g+d))^2]P
the Author had found it to be J(P,L,S,Q)=(-a -b 0 0)
(c -b 0 0)
(0 g -d 0)
(0 0 j -e) Where
a=(2(u+d)(u+g+d)+b^2)/2(u+g+d)
b=(u+g+d)/2
c=b^2/2(u+g+d)
d=u+j+d
e=(d+u)
But it is difficult for me to understand it.Please give directions towards the solution.