[填空题]
Consider the function defh :1jwetfx- tp o 47wklp.rg7kn9+ bz4;p7ytnm: nh(kv5 c kev syw,y9:4) qdqined by
$f(x)=\frac{-4 x^{2}+12}{x^{3}}, \quad x \neq 0$
1. Find an expression for $f^{\prime}(x)$ , the derivative of f(x) .
$f^{\prime}(x)$=$\frac{a(x^2-b)}{x^c}$;a= ,b= ,c= .
2. Find the equation of the tangent to the curve at the point x=1 .
at x=1 as follows y=-ax+b;a= ,b= .
3. Find the x -coordinates of the points on the curve where the gradient is zero.
$x_1$=- ,$x_2$= .
4. Determine the intervals on which f(x) is increasing.
f is increasing on the intervals (−∞,− ) and ( ,∞)
