xf(x)011k23
The function f is continuous on the closed interval [0,2] and has the values that are given in the table above.
The equation f(x)=−1 must have a least two solutions in the interval [0,2] if k=
It may be difficult to analyze this problem and use the intermediate value theorem. Sketching a graph of the points and solution equation gives us a much more intuitive view:
For f to be continous and have two solutions where f(x)=−1, we would need something like this:
The point, (1,k), must have a k-value less than −1.