What is the correct form of the verb in parenthesis? Se ____ (vender) vídeos y discos compactos.

Is the statement true or false? If it is true, give a convincing argument. If it is false, give a counterexample. A circle can always be circumscribed about a quadrilateral whose opposite angles are supplementary.

A cyclotron with dee radius 53.0 cm is operated at an oscillator frequency of 12.0 MHz to accelerate protons. What magnitude B of magnetic field is required to achieve resonance?

Use an Euler diagram to determine whether the syllogism is valid or invalid. All cats are dogs. All dogs are cows. All cows are pigs. _

$$\therefore$$

All cats are pigs.

Ultrasound of frequency 5.000 MHz reflected from red blood cells moving in an artery is found to show a frequency shift of 2.4 kHz. The speed of ultrasound in blood is

$$v = 1500 \mathrm { ms } ^ { - 1 }$$

. a. Explain why the appropriate formula for the frequency shift is

$$\frac { \Delta f } { f } = 2 \frac { u } { v }$$

, where u is the speed of the blood cells. b. Estimate the speed of the blood cells. c. In practice, a range of frequency shifts is observed. Explain this observation.

Simplify: 7.1 ÷ 4

Find the inverse Laplace transform of the given function

$$\begin{gather*} F(s) = \dfrac{5! e^{-s}}{(s - 5)^6}. \end{gather*}$$

Draw a Lewis electron dot diagram for each of the following molecules and ions. Formulate the hybridiz ation for the central atom in each case and give the molecular geometry. (a) BF3, (b) BH4, (c) PH3, (d) CS2, (e) CH^+ 3

Suppose that 260 J is conducted from a constant-temperature reservoir at 400 K to one at 100 K. What is the net change in entropy $\Delta S_{\text{net}}$ of the reservoirs in each case?

Prove that

$$P _ { \ell } ( c \mathbf { v } ) = c P _ { \ell } ( \mathbf { v } )$$

for any scalar c.

If necessary, find a few additional points and graph the function. Use the maximum number of turning point check whether it is drawn correctly.

$$f ( x ) = x ^ { 4 } - 2 x ^ { 3 } + x ^ { 2 }$$

Find the exact value of each expression.

$$\tan \theta , \text { if } \cot \theta = 2 ; 0 ^ { \circ } \leq \theta < 90 ^ { \circ }$$

Suppose y varies directly as x. Write a direct variation equation that relates x and y. Then solve. If y = 15 when x = 2, find y when x = 8.

Express each repeating decimal as a quotient of integers in lowest terms.

$$0 . \overline { 34 }$$