



 
Chris, Your method sounds way too hard. Why not simply guess what the answer must be, taking as a hint the fact that x^{4}  2x^{2}  x is "almost" a perfect square in the variable u = x^{2}  you just have to change the x into a +1. If you want the line y = mx + b to be tangent twice to the given curve, the equation that results by plugging y= mx + b in for y will have to factor into a product of 2 perfect squares in x. So try letting Chris  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 