Use scalar function with multiple input to merge statement

I have table value parameters(10).I need to implement scalar function with multiple input parameters (3 parameters)into merge statement. I have triedMerge targetable t Using source s On conditionMatched then Update...Matched not then Insert(columns...) Values(user-defined functions(s.columns..),...)-- get errors regarding function but when --I am exciting functions separatly is ----working fine