Question 30
Let $f(x)=-2x^2+8x-d$. Determine the values of the parameter $d$ such that:
a) the graph of $f$ is tangent to the $x$-axis;
b) the maximum value of $f$ is $6$;
c) $f$ is positive everywhere;
or justify why no such value of $d$ exists.
a) the graph of $f$ is tangent to the $x$-axis;
b) the maximum value of $f$ is $6$;
c) $f$ is positive everywhere;
or justify why no such value of $d$ exists.