¿Es la deforestación un recurso natural, un problema o una solución?

Two isomers (A and B) of a given compound dimerize as follows:

$$\begin{array} { l } { 2 \mathrm { A } \longrightarrow \mathrm { A } _ { 2 } } \\ { 2 \mathrm { B } \longrightarrow \mathrm { B } _ { 2 } } \end{array}$$

Both processes are known to be second order in the reactant, and $k _ { 1 }$ is known to be $0.250\ \mathrm { L }\ \mathrm { mol } ^ { - 1 }\ \mathrm { s } ^ { - 1 }$ at $25 ^ { \circ } \mathrm { C }.$ In a particular experiment A, and B were placed in separate containers at $25 ^ { \circ } \mathrm { C } ,$ where $[ \mathrm { A } ] _ { 0 } = 1.00 \times 10 ^ { - 2 }\ \mathrm { M }$ and $[ \mathrm { B } ] _ { 0 } = 2.50 \times 10 ^ { - 2 }\ \mathrm { M } .$ After each reaction had progressed for 3.00 min, [A] = 3.00[B]. In this case the rate laws are defined as follows:

$$\text {Rate} = - \frac { d [ \mathrm { A } ] } { d t } = k _ { 1 } [ \mathrm { A } ] ^ { 2 } \\ \text {Rate} = - \frac { d [ \mathrm { B } ] } { d t } = k _ { 2 } [ \mathrm { B } ] ^ { 2 }$$

Calculate the value of $k _ { 2 }.$

The first two terms of the arithmetic sequence are given. Find the missing term. Use the table feature of a graphing utility to verify your results. $a_{1}=-0.7, \quad a_{2}=-13.8, \quad a_{8}= ?$

Sketch the graph of each of the following functions: $y=\cos x$

The perimeter of an isosceles triangle is 4 times the length of the shortest side. The longer sides are 4.5 ft longer than the shortest side. What is the length of each side of the triangle?

Evaluate the given integral using the substitution (or method) indicated. $\int e^{x / 2} d x$; u=x/2

Distinguish between spring tides and neap tides?

Fill in the blank(s). A _______ is the set of all points (x, y) in a plane that are equidistant from a fixed point, called the _______ .

Use the Law of Sines to solve the triangle. $B=28^{\circ}, \quad C=104^{\circ}, \quad a=3 \frac{5}{8}$

Indica si lo que dicen estas personas es lógico o ilógico, según el contexto.

1. Nos respetabamos y por eso no nos llevábamos bien.
2. Nos ayudabamos; yo sacudía los muebles y ella lavaba la ropa.
3. Nos queríamos mucho, por eso nos veíamos todos los días.
4. No me gusta hablar con él, por eso nos contamos chistes.
5. A veces nos dábamos la mano cuando nos saludábamos.
6. Roberto está en mi clase de biología pero nunca nos vemos.

Multiple-regression analysis was used to model the abundance y of an individual bird species in transects in the United Kingdom ( Journal of Applied Ecology , Vol. 32, 1995). Three of the independent variables used in the model, all field boundary attributes, are 1. Transect location (small pasture field, small arable field, or large arable field) 2. Land use (pasture or arable) adjacent to the transect 3. Total number of trees in the transect a. Identify each of the independent variables as a quantitative or qualitative variable. b. Write a first-order model for E ( y ) as a function of the total number of trees. c. Add main-effect terms for transect location to the model you wrote in part b . Graph the hypothesized relationships of the new model. d. Add main-effect terms for land use to the model you came up with in part c . In terms of the

$$\beta ^ { \prime } s$$

of the new model, what is the slope of the relationship between E ( y ) and number of trees for any combination of transect location and land use? e. Add terms for interaction between transect location and land use to the model you arrived at in part d . Do these interaction terms affect the slope of the relationship between E ( y ) and number of trees? Explain. f. Add terms for interaction between number of trees and all coded dummy variables to the model you formulated in part e . In terms of the

$$\beta ^ { \prime } s$$

of the new model, give the slope of the relationship between E ( y ) and number of trees for each combination of transect location and land use.

Find the domain and range of the function.

$$f ( x ) = \frac { 2 } { 3 - x }$$

The amount of time t, in seconds, that it takes a simple pendulum to complete a full swing is called the period. It is given by

$$t = 2\pi \sqrt \frac{\ell}{32}$$

, where

$$\ell$$

is the length of the pendulum, in feet. Does increasing the length of the pendulum increase or decrease the period? Explain.

The table below shows the proportional relationship between Juan's pay and the hours he works. Complete the table. Plot the data and connect the points with a line. $$ \begin{matrix}\text{Hours worked} & \text{2} & \text{_} & \text{5} & \text{6}\\\mathrm{Pay ($)} & \text{40} & \text{80} & \text{_} & \text{_}\\\end{matrix} $$