how to solve it

AperennialbestsellerbyeminentmathematicianG.Polya,"HowtoSolveIt"willshowanyoneinanyfieldhowtothinkstraight.Inlucidandappealingprose,Polyarevealshowthemathematicalmethodofdemonstratingaprooforfindinganunknowncanbeofhelpinattackinganyproblemthatcanbe"reasoned"out