Tuesday

March 3, 2015

March 3, 2015

Total # Posts: 2,310

**Pre Calculus**

Solve 2cos^2(2x)=1 I divided both sides by 2 and got this cos^2(2x)=1/2 But then I didn't know what to do after that... The part that has me stumped is that it's a cos^2(2x) not just a cos^2x. Any advice on what I should try next?
*May 8, 2013*

**Chemistry**

The voltage generated by the zinc concentration cell described by, Zn(s)|Zn2 (aq, 0.100 M)||Zn2 (aq, ? M)|Zn(s) is 23.0 mV at 25°C. Calculate the concentration of the Zn2 (aq) ion at the cathode. Can someone please breakdown how to do this so I can figure out the rest of ...
*May 7, 2013*

**Chemistry **

A solution is prepared by mixing 100 mL of 0.500 M NH3 and 100 mL of 0.500 M HCl. Assuming that the volumes are additive, what is the pH of the resulting mixture? kb for ammonia is 1.8x10-5
*May 2, 2013*

**Chemistry **

A solution is prepared by mixing 100 mL of 0.500 M NH3 and 100 mL of 0.500 M HCl. Assuming that the volumes are additive, what is the pH of the resulting mixture? kb for ammonia is 1.8x10-5
*May 2, 2013*

**Health**

1:false 2:false 3:true 4:true 5:true 6:false 7:true 8:true 9:false 10:true
*May 2, 2013*

**Calc**

For z1 = 4cis(7pi/6)and z2 = 3ci(pi/3), find z1 · z2 in rectangular form. A.12 − 12i B.-12 − 12i C.12 + 12i D.12i E.-12i
*April 29, 2013*

**Physics**

To combat wasteful habits, we often speak of “conserving energy,” by which we mean turning off lights, heating or cooling systems, and hot water when not being used. In this chapter, we also speak of “energy conservation.” Distinguish between these two ...
*April 28, 2013*

**Physics**

When you jump upward, your hang time is the time your feet are off the ground. Does hang time depend on your vertical component of velocity when you jump, your horizontal component of velocity, or both? Defend your answer. Please help!!! Thank you in advance...
*April 28, 2013*

**Physics**

To combat wasteful habits, we often speak of “conserving energy,” by which we mean turning off lights, heating or cooling systems, and hot water when not being used. In this chapter, we also speak of “energy conservation.” Distinguish between these two usages.
*April 28, 2013*

**Physics**

A park ranger wants to shoot a monkey hanging from a branch of a tree with a tranquilizing dart. The ranger aims directly at the monkey, not realizing that the dart will follow a parabolic path and thus will fall below the monkey. The monkey, however, sees the dart leave the ...
*April 28, 2013*

**Physical Science**

A park ranger wants to shoot a monkey hanging from a branch of a tree with a tranquilizing dart. The ranger aims directly at the monkey, not realizing that the dart will follow a parabolic path and thus will fall below the monkey. The monkey, however, sees the dart leave the ...
*April 27, 2013*

**physics**

To combat wasteful habits, we often speak of “conserving energy,” by which we mean turning off lights, heating or cooling systems, and hot water when not being used. In this chapter, we also speak of “energy conservation.” Distinguish between these two usages.
*April 27, 2013*

**physics**

Why bother using a machine if it cannot multiply work input to achieve greater work output?
*April 27, 2013*

**physics**

When a cannon with a longer barrel is fired, the force of expanding gases acts on the cannonball for a longer distance. What effect does this have on the velocity of the emerging cannonball? (Do you see why long-range cannons have such long barrels?)
*April 27, 2013*

**Physics**

In grandpa’s time automobiles were previously manufactured to be as rigid as possible, whereas autos are now designed to crumple upon impact. Why?
*April 27, 2013*

**Calc**

If z = 2cis 60°, find z^4 in rectangular form. A.-8+8sqrt(3i) B.-8-8sqrt(3i) C.8+8sqrt(3i) D.8-8sqrt(3i) E.16-16Sqrt(3i)
*April 26, 2013*

**Vectors/Math**

If w = <-8, 15>, find ||w||. A. 7 B. 17 C. 23 D.sqrt 7 E.sqrt 23
*April 26, 2013*

**Calc**

Which functions of x and y in terms of time t can be derived from this rectangular equation? (x^2/4)+y^2=1 A. x = 2sin t, y = -cos t B. x = sin t, y = 5cos t C. x = sin t, y = 2cos t D. x = -sin t, y = 2cos t E. x = 2sin t, y = 5cos t
*April 26, 2013*

**Physics**

A park ranger wants to shoot a monkey hanging from a branch of a tree with a tranquilizing dart. The ranger aims directly at the monkey, not realizing that the dart will follow a parabolic path and thus will fall below the monkey. The monkey, however, sees the dart leave the ...
*April 25, 2013*

**Physics**

Why do the passengers in high-altitude jet planes feel the sensation of weight while passengers in the International Space Station do not? Please help; need an original answer no Google search. Thank you in advance...
*April 25, 2013*

**Physics**

What would be the path of the Moon if somehow all gravitational forces on it vanished to zero? Please help; need an original answer no Google search. Thank you in advance...
*April 25, 2013*

**Physics**

What would be the path of the Moon if somehow all gravitational forces on it vanished to zero? Please help; need an original answer no Google search. Thank you in advance...
*April 25, 2013*

**Physics**

To combat wasteful habits, we often speak of “conserving energy,” by which we mean turning off lights, heating or cooling systems, and hot water when not being used. In this chapter, we also speak of “energy conservation.” Distinguish between these two ...
*April 25, 2013*

**Physics**

Why bother using a machine if it cannot multiply work input to achieve greater work output? Please help; need a original answer no Google search. Thank you in advance...
*April 25, 2013*

**Physics**

When a cannon with a longer barrel is fired, the force of expanding gases acts on the cannonball for a longer distance. What effect does this have on the velocity of the emerging cannonball? (Do you see why long-range cannons have such long barrels?) Please help; need a ...
*April 25, 2013*

**Physics**

In grandpa’s time automobiles were previously manufactured to be as rigid as possible, whereas autos are now designed to crumple upon impact. Why? Please help; Thank you in advance for the help...
*April 25, 2013*

**Calc**

In the first three days of its launch, the Galaxy Music Store sold 14 CDs of album x, 8 of album y, and 6 of album z through Branch A. Through Branch B, the store sold 7 CDs of album x, 13 of album y, and 4 of album z. Branch C sold 2 CDs of album x, 11 of album y, and 1 of ...
*April 25, 2013*

**Calc**

If w = <-8, 15>, find ||w||. A. 7 B. 17 C. 23 D.sqrt 7 E. sqrt 23
*April 25, 2013*

**Calc**

Which expression is equivalent to (sin x + 1)(sin x − 1)? A. cos2^x B. -cos2^x C. cos2^x + 1 D. cos^2x − 1 E. -cos^2x + 1
*April 25, 2013*

**Calc**

A video games shop is analyzing its sales performance using matrices. Matrix A contains the unit sales data for each product category (horizontally) per week (vertically). Matrix B contains the unit sales data for weekends for each category (horizontally) per week (vertically...
*April 25, 2013*

**Math, Calc**

Which rectangular equation corresponds to this set of parametric equations? x = t + 2 and y = t^2 + 3 A. y = (x − 2)^2 − 3 B. y = (x + 2)^2 + 3 C. y = (x − 2)^2 D. y = (x + 2)^2 − 3 E. y = (x − 2)^2 + 3
*April 25, 2013*

**math 7th**

Thanks Ms. Sue I see what I forgot to do.
*April 24, 2013*

**math 7th**

When the temperature is 68°F, the speed of sound in air is approximately 343 meters per second. Approximately how many kilometers does sound travel in five seconds? Can some one help with the steps?
*April 24, 2013*

**Eco103**

Given The demand function of a product q=f (a)= 3600-15p find the maximizes total revenue and quanty sold
*April 23, 2013*

**algebra 2**

a two-digit counting number has a value that is 13 greater than 3 times the sum of the digits. If the units digit is 1 greater than the tens digit, what is the number
*April 23, 2013*

**Math**

how to you multiply fractions (not mixed numbers)
*April 18, 2013*

**algebra 2**

10,000 raffle tickets were sold and you buy 12 tickets. Whats the odds against winning
*April 18, 2013*

**Calc**

What is the solution of this system? 2x + 3y = 32 11y − 2x = 52 A. x = 3/2 , y = 5 B. x = 4, y = 8 C. x = 7, y = 6 D. x = 10, y = 4 E. x = 8, y = 16/3
*April 18, 2013*

**Calc**

Which expression is equivalent to sin(3x) + sin x? A. 2cos(2x)sin x B. 2sin(2x)sin x C. -2sin(2x)cos x D. 2sin(2x)cos x E. -2cos(2x)sin x
*April 18, 2013*

**Calc**

Which rectangular equation corresponds to this set of parametric equations? x = t + 2 and y = t^2 + 3 A. y = (x − 2)^2 − 3 B. y = (x + 2)%2 + 3 C. y = (x − 2)^2 D. y = (x + 2)^2 − 3 E. y = (x − 2)^2 + 3
*April 18, 2013*

**geometry**

Is this syllogism? 1. In-line skaters live dangerously. 2.if you live dangerously, then you like to dance. 3, If you are an in-line skater, then you like to dance.
*April 17, 2013*

**geometry**

Is this an invaild arguement?
*April 17, 2013*

**Physics**

A string of mass 0.0003 kg/m and 0.5m long is vibrating 200 cycles per second. What must be the tension? What hanging mass would produce the tension?
*April 16, 2013*

**Alg 1**

also i^2=-1
*April 15, 2013*

**Alg 1**

sorry there was a miscalculation. Det x = 1-80=-79 not -39
*April 15, 2013*

**Alg 1**

Det x = b^2 - 4ac - formula x = -b +/- sqrt Det x/2a - formula if Det x = 0 then x has only 1 solution Det x > 0 then x has 2 solutions Det x <0 then x has 2 complex solutions - a+ib=z, z is a complex number, i^2=-i, a is the real part b is the imaginary one Det x = 1-40...
*April 15, 2013*

**algebraic systems**

ok, so im stumped on this bonus system. there is a hint that the prof. gave that said that all coefficients are 1 or -1. can someone do this and explain how you did it? a + b + c + d + e + f + g + h + k + m = 27 a – b + c + d + e + f + g + h + k + m = 23 a + b - c + d + e...
*April 15, 2013*

**chemistry**

net ionic equations for Ca(NO3)2 +NaPO4
*April 15, 2013*

**stats**

Cushman and Wakefield accounting that the average annual rent for office space in Tampa was $17.63 per square foot. A real estate agent selected a random sample of 15 rental properties (offices) and found that mean rent was $18.72 per square foot and s= $3.64. At a= 0.05, test...
*April 13, 2013*

**math**

All varieties of a certain brand of cookies are $3.50 A person buys peanut butter and chocolate chip cookies. Write an expression that tepresents the total cost.
*April 9, 2013*

**math**

All varieties of a certain brand of cookies are $3.50 A person buys peanut butter and chocolate chip cookies. Write an expression that tepresents the total cost.
*April 9, 2013*

**Check answers please Statistics**

Suppose that each student in stat. has a 9% chance of missing class on any given day and that student attendance is independent. In a stat. class of 20 students, find the probability that: 1) no student is absent =15.16 2) one student is absent =30 3) three student is absent =...
*April 8, 2013*

**Math Help **

Suppose that each student in stat. has a 9% chance of missing class on any given day and that student attendance is independent. In a stat. class of 20 students, find the probability that: 1) no student is absent 2) one student is absent 3) three student is absent 4) at least ...
*April 8, 2013*

**math**

Math systems 3x-2y-z=-20 x-y=10
*April 8, 2013*

**stats**

The president of a large university wishes to estimate the average age of the students presently enrolled. From past studies, the standard deviation ó is known to be 2 years. A sample of 50 students is selected and the mean is found to be 23.3 years. a. Find the 99% ...
*April 7, 2013*

**stats.**

so 2.575=10/what would n be?
*April 7, 2013*

**stats.**

One hundred subjects in a psychological study had a mean of 35 on a test instrument designed to measure anger. The study the ó=10. Find a 99% confidence interval for the mean anger score of the population.
*April 7, 2013*

**stats.**

In a transportation study of 20 large cities, it was found that the mean of the number of cars per person was 0.504. (Some of the people in the city are children.) The study also stated that the standard deviation s was 0.123. Find a 95 % confidence interval for the true mean ...
*April 4, 2013*

**Math- Partial Fractions**

Decompose the following into partial fractions after factoring the denominator as much as possible. Please show some work so I can understand how you did it. 1)x^2/((x-1)(x^2+5x+4)) 2)(3x^3-5x^2+12x+4)/(x^4-16) 3)1/(x^2 (x+1)^2 ) 4)(x+1)/((x^2+1) 〖(x-1)〗^2
*April 4, 2013*

**stats**

given n=74 an x=32.find ^p and ^q
*April 4, 2013*

**math**

the perimeter of a triangle is 79.75 inches. the second side of the triangle is half as big as the first side. the third side is 7.25 in greater than the first side what is the length of the longest side of the triangle?
*April 3, 2013*

**stats.**

The mean number of bumped airline passengers per day s 1.35 and the standard deviation is 0.25. For a random selection of a group of 40 days, what is the probability that the mean number of bumped passengers for the 40 days will be between 1.25 and 1.50?
*April 2, 2013*

**stats.**

The amount that airlines spend on food per passenger is normally distributed with mean $8.00 and standard deviation $2.00. What is the probability that a randomly selected airline spends more than $12.50.
*April 2, 2013*

**stats**

Given a standard normal variable. What is the probability that z lies between 1.48 and 2.13
*April 2, 2013*

**Math**

An object at rest begins moving horizontally on the x-axis, starting at position x(t) = 0 feet at time t = 0 seconds.Suppose, after exactly 2 seconds we measure the position of the object to be 3 feet to the right of the origin AND measure the object to be moving to the ...
*April 1, 2013*

**Math/ Calculus Please HELP!!!**

hey thanks but i still dont get how you arrived to this answer?
*April 1, 2013*

**Math**

how many even 4 digit whole numbers exisit such that the thousands digit it odd all 4 digits different
*March 31, 2013*

**stats**

I am so lost I know the mean is 0.504 so is the SEM 1.96?
*March 31, 2013*

**stats**

n a transportation study of 20 large cities, it was found that the mean of the number of cars per person was 0.504. (Some of the people in the city are children.) The study also stated that the standard deviation s was 0.123. Find a 95 % confidence interval for the true mean ...
*March 31, 2013*

**stats**

what is n
*March 31, 2013*

**stats**

One hundred subjects in a psychological study had a mean of 35 on a test instrument designed to measure anger. The study the ó=10. Find a 99% confidence interval for the mean anger score of the population.
*March 31, 2013*

**stats**

The standard deviations s for the annual medical costs 30 heart disease patients was found to equal $1005. Find a 95 % confidence interval for the standard deviation of the annual medical costs for all heart disease patients.
*March 31, 2013*

**stats**

In a transportation study of 20 large cities, it was found that the mean of the number of cars per person was 0.504. (Some of the people in the city are children.) The study also stated that the standard deviation s was 0.123. Find a 95 % confidence interval for the true mean ...
*March 31, 2013*

**math**

thank you
*March 28, 2013*

**math**

mary jogged 5 7/10 miles on monday and 4 1/8 miles on tuesday. Raul jogged 6 1/2 miles on monday and 3 4/5 miles on tuesday. How much farther did raul jog on monday than tuesday.
*March 28, 2013*

**algebra**

The perimeter of a triangle is 47 miles. The first side is 5 miles less than twice the second and the third is 2 miles more than the first. Find the lengths of each side.
*March 28, 2013*

**math**

find the rule: X=8,9, 10,11,12 y=8,10,12,14,16
*March 27, 2013*

**Chem**

Calculate [H3O ], [ClO4–], and [OH–] in an aqueous solution that is 0.170 M in HClO4(aq) at 25 °C.
*March 27, 2013*

**history**

It is Populist . Correct.
*March 25, 2013*

**Chemistry**

Calculate the volume of 0.3MHCL used to neutralise NaOH solution
*March 25, 2013*

**Math/ Calculus Please HELP!!!**

A truck driver, on assignment from the owner of the truck is to drive on a 300 mile stretch of highway at a constant speed of v miles per hour. According to road signs, the minimum speed allowed is 55 miles per hour and the speed limit is 70 miles per hour. The cost of gas on ...
*March 24, 2013*

**math**

A girl 1.6 m tall, stands 3.6 m from a lamp post at night. Her shadow from the light is 0.9m long. How high is the lamp post?
*March 20, 2013*

**math**

the increasing global temperature can be modeled by I=0.1e^(0.02t) where I is the increase in global temperature in degrees Celsius since 1990 and t is the number of years since 1990. How much warmer was it in 2000 than in 1950? iIn what year will the temp be 4 degrees Celsius...
*March 18, 2013*

**Chemistry**

Is the dissolution of calcium sulfate endothermic or exothermic? How do you know?
*March 17, 2013*

**stats**

The amount that airlines speed on food per passenger is normally distributed with means $8.00 and standard deviation $2.00. What is the probability that a randomly selected airline spends more than $12.50?
*March 17, 2013*

**stat.**

The average age of a vehicle registered in the United States is 8 years, or 96 months. Assume the standard deviation is 16 months. If a random sample of a group of 48 vehicles is selected find the probability that the mean of the group’s age is between 90 and 100 months.
*March 17, 2013*

**accounting**

Dan and Joan want to buy an airplane. They find one that will cost $200,000. They must pay 10% down, and can get the balance financed with a 10 year loan at 7% interest and annual payments. What is their annual payment? Answer $26,826 $25,626 $24,457 $19,260
*March 16, 2013*

**Chemistry**

Write a balanced equation for the following: aqueous barium chloride reacts with aqueous sodium chromate to form aqueous sodium chloride plus solid barium chromate.
*March 14, 2013*

**chemistry**

I got .369 g Rh(OH)3. RIGHT?
*March 14, 2013*

**Chemistry**

hey i got Sb2O5 for the oxide is O5 right?
*March 14, 2013*

**Ms. Sue please science**

yea sweet cheeks;)....your welcome.
*March 13, 2013*

**Chem 1**

is there a formula that i am suppose to use?
*March 13, 2013*

**Chem 1**

The forensic technician at a crime scene has just prepared a luminol stock solution by adding 15.0g of luminol into a total volume of 75.0 \rm mL of \rm H_2O. What is the molarity of the stock solution of luminol? 1.13M Before investigating the scene, the technician must ...
*March 13, 2013*

**Physics 11**

Sorry, I typed the equation wrong. This is the correct one. "Displacement is given by x=2+3t+4t². Find teh value of instantaneous acceleration." I still don't understand how to go about this. Thanks.
*March 13, 2013*

**physics 11**

Displacement i sgivenby x=2+3t+4t2. Find the value of instantaneous acceleration.
*March 13, 2013*

**Life oriantation**

Identify 5 practices in above case study that are in contravention of the basic condition of employment act
*March 10, 2013*

**physics**

The density of ice is 917 kg/m3, and the density of sea water is 1025 kg/m3. As shown is the figure, a polar bear climbs onto a piece of ice, which has a volume of 5.75 m3, and is floating in sea water. a) What is the mass of the piece of ice? b) What is the mass of the ...
*March 9, 2013*

**math**

The cashier got 1/3 of the stamps and the secretary got 1/5 of the stamps. The secretary got 40 fewer stamps than the cashier. How many did the cashier receive?
*March 8, 2013*

**Chemistry**

Determine the boiling point of a solution contanting 36.1grams calcium chloride molar mass 112 in 200.0grams water.
*March 7, 2013*

**Chemistry**

The molal freezing point constant(Kf) for acetic acid is 3.90 C/m. When 31.5 grams of unknown solute is dissolved in 650 grams of acid the freezing point is lowered by 0.79 what is the molar mass
*March 7, 2013*

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