dedicated memory for LUT(look up table) on cyclone 2 ???

Please download the Cyclong II handbook:

http://www.altera.com/literature/lit-cyc2.jsp

You don't have to read it word for word, but it goes over device resources(PLLs, M4Ks, DSP blocks, IO standards, etc.). For instantiating memory(like a COS/SIN table), the Quartus II handbook goes into inferring these in VHDL or Verilog. Probably the easiest is to use the Megawizard to create a ROM, and then you create a Memory Initialization File with the contents you want(the output of the MegaWizard can be instantiated into VHDL/Verilog/schematic/etc.)

There's a lot of good information in the literature on the website. If you go through that and then ask questions, you'll get better responses, as most posters don't want to reiterate what's already in the documentation.

Hope that gets you going in the right direction.