Question 7
(a) Determine $m$ so that $x^2+(2m+6)x+4m+12=0$ has two real roots both greater than $-1$.
(b) Differentiate
$$f(u)=\frac{u+\sqrt{u^2+1}}{\sqrt{1+u^2}-u}+\frac{\sqrt{1+u^2}-u}{u+\sqrt{1+u^2}}.$$
(b) Differentiate
$$f(u)=\frac{u+\sqrt{u^2+1}}{\sqrt{1+u^2}-u}+\frac{\sqrt{1+u^2}-u}{u+\sqrt{1+u^2}}.$$