A rancher has 800 feet of fencing to put around a rectangular field and then subdivide the field into 3 identical smaller rectangular plots by placing two fences parallel to one of the field's shorter sides. Find the dimensions that maximize the enclosed area. Write your answers as fractions reduced to lowest terms.

1. \( \lim _{x \rightarrow \infty}(\overline{3 x-5}) \) 2. \( \lim _{x \rightarrow 0}(1-\tan x)^{\frac{4 x}{\sin ^{2} 3 x}} \)

\( \int \frac { 3 / \sqrt { a ^ { 3 } y ^ { 4 } } x d x } { 4 / 3 a ^ { 2 } b ^ { 3 } x ^ { 2 } + 6 } \)

9.- Calcula la derivada de la función * \( y=\left(x^{2}+b^{2}\right)^{4} \) \( \begin{array}{ll}\text { A) } \frac{d y}{d x} 8 x\left(x^{2}+b^{2}\right)^{5} & \text { B) } \frac{d y}{d x} 8 x^{2}\left(x^{2}+b\right)^{3} \\ \text { C) } \frac{d y}{d x} 8 x\left(x^{2}+b^{2}\right)^{3} & \text { D) } \frac{d y}{d x} 8\left(x^{2}+b^{2}\right)^{3}\end{array} \)

1) \( \int_{8}^{\frac{\text { III }}{\frac{\pi}{2}}} x \cdot c \)

7.- Resuelve el siguiente límite * \( \operatorname{lí}_{t \rightarrow 1}\left(\frac{t^{2}+2 t+1}{2 t-4}\right) \) 2 -3 -2 3