Find the equation whose roots are reciprocals of the roots of 2x2+5x+4=0 .
5x2+4x+2=0
4x2+5x+2=0
4x2+2x+5=0
2x2+4x+5=0
To get the equation whose roots are reciprocals, replace x by 1x.
⇒2×1x2+5x+4=0
Multiplying by x2, ( x≠0)
⇒2+5x+4x2=0 or 4x2+5x+2=0