[填空题]
Consider the function defi//;r nlpb zvtq8cw 6(ened byy+l7- 5ltnew ( iq*qyu
$f(x)=\frac{8 x^{2}}{3 x^{3}+x}, x \quad \neq 0$
1. Find an expression for $f^{\prime}(x)$ , the derivative of f(x) .
f'(x)=$\frac{-ax^4+bx^2}{(3x^3+cx)^2}$;a= ,b= ,c= .
2. Find the equation of the tangent to the curve at the point x=1 .
y=-ax+b;a= ,b= .
3 . Find the x -coordinates of the points on the curve where the gradient is zero.x=$\pm \frac{1}{\sqrt{a}}$;a= .
4. Determine the intervals on which f(x) is increasing.
