FunctionInterpolation

FunctionInterpolation[expr,{x,xmin,xmax}] evaluates expr with x running from xmin to xmax and constructs an InterpolatingFunction object which represents an approximate function corresponding to the result. 

FunctionInterpolation[expr,{x,xmin,xmax},{y,ymin,ymax},…] constructs an InterpolatingFunction object with several arguments. 

Please visit the official Wolfram Language Reference for more details and examples on core symbols.