[填空题]
Let $f(x)=\sqrt{2 x+1}$ for $x \geq-0.5$ .
1. Find
a. $f(12)$ ;
b. $f^{\prime}(12)$
Consider another function g(x) . Let P be a point on the graph g . The x -coordinate of P is 12 . The equation of the tangent to the graph at P is y=x+3 .
2. Write down $g^{\prime}(12)$ .
3. Find g(12) .
4. Let $ h(x)=f(x) \times g(x) $. Find the equation of the tangent of h at the point where x=12 .
