[sage-support] PyQt on Sage 4.4 doesn't 'make'

Hi, does anybody know how I can install PyQt4-4.6.2 on Sage 4.4.1? I first installed sip-4.9.3 (both spkg) and then after a while of compiling i got the following error: /usr/bin/ld: cannot find -lXext collect2: ld returned 1 exit status make[1]: *** [QtCore.so] Error 1 make[1]: Leaving directory

[sage-support] substitute_function - but?

I tried to do some calculations and used a self-defined function. After that, I wanted to change it to another function like sin or just a constant. I am using the binary version on Ubuntu Karmic. What I got was the following: --