How solve this problem

//Warning: Cycle on " expression3.output[o]" may not eavaluate as expected. (Use “cycleCheck -e off” disable this warning ).
how will i solve this problem ? please tell me

First, Maya figures out the output of expression3, and then tells that value to other nodes. That value is then used in other calculations, and then those results are given back to expression3. Expression3 already figured out it’s output value and it doesn’t want to do it again. If it did, it would just get another value to do calculations with, over and over again, forever. This is a cycle.

You have something like this in your file.

Without knowing what’s in your scene, we can’t know how the output of expression3 is connected back to the input.

You should be able to find this cycle by using the node editor, or using the mel cycleCheck command.