Evaluate: \( \lim _{x \rightarrow \frac{\pi}{4}} \frac{\sec ^{2} x-2 \tan x}{1+\cos 4 x} \)

Use the given function to complete parts (a) through (e) below. \( f(x)=x^{4}-36 x^{2} \) At which zeros does the graph of the function touch the \( x \)-axis and turn around? Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. \( x=\square \) (Type an integer or a decimal. Use a comma to separate answers as needed.) B. There are no \( x \)-intercepts at which the graph touches the \( x \)-axis and turns around.

Use the given function to complete parts (a) through (e) below. \( f(x)=x^{4}-36 x^{2} \) c) Find the \( y \)-intercept by computing \( f(0) \). \( f(0)= \) d) Determine the symmetry of the graph. Odd; origin symmetry Even; \( y \)-axis symmetry Neither

Find the average rate of change of the function \( f(x)=x^{2}+9 x \) from \( x_{1}=1 \) to \( x_{2}=2 \). The average rate of change is \( \square \). (Simplify your answer.)

\( \lim _ { x \rightarrow 0 } ( \frac { a - \cos ( \underline { 3 } x ) } { x - \sin ( b x ) } ) = ? \)

\begin{tabular}{l} (1) \( f(x)=3 x^{3}+2 x^{2}-5 x-10 \) \\ a) \( \int_{3}^{8} f(b)-f(a)= \) \\ b) Derivada \\ c) Velocidad \( \quad{ }_{m}=\frac{f\left(x_{i}\right)-f(x i)}{x_{f}-x_{i}} \quad[3,5] \) \\ \hline\end{tabular}