The graph of the function y=x^2+ax+1 touches to the X-axis if and only if a=?
To complete this problem, we will use the discriminant . This provides information about the roots of an equation.
It is modelled after the quadratic form
- If the discriminant is positive, the quadratic has two roots.
- If the discriminant is negative, the quadratic has no roots.
- If the discriminant is
#0#, the quadratic has #1#root.
In this example, we must use the last case, because we are looking for the point where the quadratic touches the
We know that, in this problem,