Saved Bookmarks
| 1. |
12 Write the positive root of a quadretic equation ac+bx+c=0 |
|
Answer» To say that the roots ofax2+bx+c=0are imaginary is to say that the graph of: f(x)=ax2+bx+c does not intersect thexaxis for any real value ofx. Since this is described as a quadratic, we must havea≠0. So the whole of the parabo, one side of thexaxis or the other. When we multiply bya≠0, gettinga2x2+abx+acwhose graph is simply a scaled version of the original, the coefficient ofx2isa2>0. Hence we know that for large values ofxthe quadratic function will be positive. Hence it is positive for all values ofx. |
|