Sunday

December 4, 2016
Total # Posts: 1,419

**Trigonometry**

Use the trigonometric subtraction formula for sine to verify this identity: sin((π / 2) – x) = cos x

*May 10, 2015*

**Trigonometry**

Can you show steps on deriving the identity from the sum and difference formulas for cosine: sin a sin b = (1 / 2)[cos(a – b) – cos(a + b)]

*May 10, 2015*

**ap chemistry**

going left

*May 9, 2015*

**phi 208**

kants just war theory

*May 9, 2015*

**Math**

Find the level of elevation of the sun when a 842 foot building casts a shadow72.6 feet long

*May 6, 2015*

**college precalculus**

Saving. How much money should be invested monthly at 6% per year, compounded monthly, in order to have $2000 in 8 months?

*May 5, 2015*

**Math**

Find the volume of a regular square pyramid that is 8 m high and has the length of the side of the base as 9 m

*April 29, 2015*

**Math**

The lens of a telescope has a diameter of 24 inches. Find the exact area of the lens.

*April 29, 2015*

**chemistry**

Did I round to the correct number of Sig figs? 18.0/83 x 100= 22% 15.87/149.87x 100= 11.3%

*April 16, 2015*

**Chemistry**

What is the maximum mass of H2O that can be produced by combining 71.7 g of each reactant? 4NH3 (g) + 5O2 (g) -----> 4NO (g) + 6H2O (g) ___________ g H2O ?

*April 14, 2015*

**Chemistry**

What is the maximum mass of S8 that can be produced by combining 85.0 g of each reactant? 8SO2 + 16H2S yields 3S8 +16H2O

*April 14, 2015*

**Chemistry: Acids/Bases**

When a 100 mM aq solution of sodium acetate was prepared in the lab it had a pH of 8.9. Calculate the amount of acetic acid (in g) to be added to 0.5 L of this sodium acetate solution in order to bring its pH to the target value of 5.00.

*April 11, 2015*

**chemistry**

I understand part (I) but We have only briefly gone over the HH equation in class and I understand how to use it to get the pH but I really don't understand how to use it in part (II), assuming I should be using it in this question? (I)Calculate the pH of an acetate buffer...

*April 10, 2015*

**Math**

Use logarithmic differentiation to find the derivative of y: y=x^(e^x)

*March 30, 2015*

**math**

if I bought 3 items at 24.95 and 2 items at 45 and they were all 30% off, If I had bought these 5 items without the 30$ off what would I have paid

*March 20, 2015*

**economics**

Samantha Roberts has a job as a pharmacist earning $30,000 per year, and she is deciding whether to take another job as the manager of another pharmacy for $40,000 per year or to purchase a pharmacy that generates a revenue of $200,000 per year. To purchase the pharmacy, ...

*March 20, 2015*

**economics**

Samantha Roberts has a job as a pharmacist earning $30,000 per year, and she is deciding whether to take another job as the manager of another pharmacy for $40,000 per year or to purchase a pharmacy that generates a revenue of $200,000 per year. To purchase the pharmacy, ...

*March 20, 2015*

**algebra**

Is the answer 10 w + 3w = 13w 11-8 = 3 13w -3?

*March 18, 2015*

**algebra**

10w + 11 - 3w -8

*March 18, 2015*

**statistics**

47

*February 22, 2015*

**social problems**

patriarchy

*February 12, 2015*

**math **

A farmer wants to fence a small rectangular yard next to a barn. Fence for side parallel to the barn will cost 75 per foot and the fence for the other two sides will cost 30 per foot. The farmer has a total of 1750 dollars to spend on the project. Find the dimensions for the ...

*February 12, 2015*

**Physics**

a BALL IS THROWN UPWARD WITH AN INITIAL VELOCITY OF 9.8 M/S FROM THE TOP OF A BUILDING. FILL A TABLE BELOW SHOWING THE BALLS POSITION,VELOCITY, and ACCELERATION AT THE END OF EACH OF THE 1ST 4SEC OF MOTION TIME(s) POSITION(M) VELOCITY(M/S) 1 2 3 4 Acceleration (M?S^2) Fill in ...

*February 11, 2015*

**Physics**

During a rElay race along a straight ROAD the 1st runner on a three person team runs D1 with a constant velocity v1. The runner then hands off the baton to the sEcond runner who runs d2 with a constant vElocity v2. The batton is then passed to the 3rd runner who completes the ...

*February 11, 2015*

**Physics**

For a science fair competition, a group of High School students built a kicker-machine that can launch a golf ball from the origin with a velocity of 12.9 m/s and initial angle of 31.7° with respect to the horizontal. a) Where will the golf ball fall back to the ground? ...

*January 27, 2015*

**language arts**

No, it is still CBC.

*January 6, 2015*

**World history**

i don't understand what you mean

*January 2, 2015*

**World history**

I need help on a artistic response to the contemporary world im not creative i need help please im thinking to do one on war or violence

*January 2, 2015*

**Just out of curiosity**

So I believe you're American. Am I right?

*December 14, 2014*

**Just out of curiosity**

Oh that's nice of you guys! (: So who is the founder of this site? Are tutors here American?

*December 14, 2014*

**Just out of curiosity**

Are the teachers here getting paid to help the students? Is this a paid program?

*December 14, 2014*

**Chemistry**

1) A 0.1375-g sample of solid magnesium is burned in a constant-volume bomb calorimeter that has a heat capacity of 3024 J/C. The temperature increases by 1.126 degrees C. Calculate the heat given off by the burning Mg, in kJ/g and kJ/mol. 2) Determine the amount of heat in kJ...

*November 18, 2014*

**Chemistry**

1) Determine the amount of heat in kJ given off when 1.26 x 10^4 g of NO2 are produced according to the equation: 2NO (g) + O2 (g) --> 2NO2 (g) and delta (H) = 483.6 kJ/mol 2) A sheet of gold weighing 10 g and at a temperature of 18 degrees C is placed on a flat sheet of ...

*November 18, 2014*

**physics**

What is the kinetic energy in MeV of a π–meson that lives 1.80×10-16 s as measured in the laboratory, and 0.840×10-16 s when at rest relative to an observer, given that its rest energy is 135 MeV?

*November 16, 2014*

**Maths**

4. Tonya is 1.3 meters tall. She stands 7 meters in front of a tree and casts a shadow 1.8 meters long. How tall is the tree?

*November 12, 2014*

**math**

a box of chalk and 2 staplers costs $10. 3 boxes of chalk and 2 staplers costs $18. find total cost of 1 box of chalk and 1 stapler

*October 30, 2014*

**precalculus**

one section of a suspension bridge has its weight uniformly distributed between twin towers that are 400 feet apart and rise 90 feet above the horizontal roadway. a cable strung between the tops of the towers has the shape of a parabola, and its center point is 10 feet above ...

*October 25, 2014*

**Physics**

as you are riding in a 1650-kg car, you approach a hairpin curve in the road whose radius is 50m. the roadbed is banked inward at anangle of 10 degrees. suppose that the road is dry and that the static friction coefficient between the tires and the asphalt road is .6 what is ...

*October 24, 2014*

**inequalities**

5(2x-4)+ 11< 10 -2(6-x)

*October 21, 2014*

**Math**

If z^2 = x^2 + y^2 with z>0, dx/dt=3, and dy/dt=6, find dz/dt when x=4 and y=3. Answer: \displaystyle \frac{dz}{dt} =

*October 20, 2014*

**Calculus**

At noon, ship A is 40 nautical miles due west of ship B. Ship A is sailing west at 19 knots and ship B is sailing north at 16 knots. How fast (in knots) is the distance between the ships changing at 7 PM?

*October 20, 2014*

**Chem---DrBob222**

What is the formula for 2-bromomethylpropane ?

*October 14, 2014*

**Physics**

A highway curve with a radius of 750 m is banked properly for a car traveling 100 km/h. If a 1600- kg Porshe 928S rounds the curve at 220 km/h, how much sideways force must the tires exert against the road if the car does not skid?

*October 10, 2014*

**Physics**

Use kinematic equations,velocity at max height is zero, so 0=9.75^2-19.6(X-399)=403.9m. Then for speed at ground just do V^2=-19.6(0-403)=88.9 m/s

*October 10, 2014*

**Physics Help Please!!!!**

1) A high-speed maglev train is traveling with a changing velocity. what can be said about the forces acting on the train? 2) An automated vehicle in a warehouse is traveling at a constant velocity. what can be said about the forces acting on the vehicle?

*October 1, 2014*

**math**

out of 32 students in a class, 5 said they rode their bikes to school. Based on these results, how many of the 800 students ride their bikes to school?

*September 28, 2014*

**English**

Thank you SO MUCH.

*September 24, 2014*

**English**

Which would be grammatically correct: We both had a goal and objective in mind to get our jobs done. or We both had a goal and objective in mind to get the job done. Thanks!

*September 24, 2014*

**Algebra Based - Physics Help Please!!!!**

a) In 1897, Madeline Boardman won the long-drive contest during the U.S. Women's Amateur Golf Tournament. Her winning drive was 125 m. if the ball was hit off the tee at a 45 degree angle, what did the magnitude of its initial velocity have to be for her to make the ...

*September 24, 2014*

**Physics - Force**

A high-speed maglev train is traveling with a changing velocity. what can be said about the forces acting on the train? Thanks!

*September 24, 2014*

**physics**

If a pull of 350 N accelerates a 38-kg child on ice skates at a rate of 7.3 \frac{m}{s^2}, what is the frictional force acting on the skate?

*September 15, 2014*

**Physics Help Please**

a) On the Acme W&W company production line, parts have to be transported 100 m by conveyor belt to a machine area. The parts move at a constant speed of 2.5 m/s. How much time does it take to move a part 100 m? b) On the same conveyor belt as described in problem a), the part ...

*September 11, 2014*

**Physics Help**

a) On the Acme W&W company production line, parts have to be transported 100 m by conveyor belt to a machine area. The parts move at a constant speed of 2.5 m/s. How much time does it take to move a part 100 m? On the same conveyor belt as described in problem a), the part ...

*September 11, 2014*

**Physics Help**

On the Acme W&W company production line, parts have to be transported 100 m by conveyor belt to a machine area. The parts move at a constant speed of 2.5 m/s. How much time does it take to move a part 100 m? Show steps please! Thank you!

*September 11, 2014*

**6th Grade Math**

Thank you to all that helped

*September 2, 2014*

**6th Grade Math**

Can someone please show me how to work this problem below? Jacob earned $80 babysitting and deposited the money into his savings account. The next week he sepnt $85 on video games. Use the integers to describe the weekly changes in Jacob's saving account balance.

*September 2, 2014*

**Statics**

If both the projection Pa and component Fb of the force F are 305 N, determine the magnitude F and the orientation è of the b-axis. The angle between the negative y axis and the a- axis is 70 degrees. The angle between the negative y axis and the force F is 108 degrees...

*September 1, 2014*

**Statics**

The figure shown includes an x, y, and z axis. On the positive x-y plane, force F2 points toward the origin with a magnitude of 3kN and an angle theta between it and the positive x axis. On the negative x-y plane, force F1 points toward the origin with an angle of 27 degrees ...

*September 1, 2014*

**Statics**

The two forces shown act in the x-y plane of the T-beam cross section. If it is known that the resultant R of the two forces has a magnitude of 3.8 kN and a line of action that lies 14° above the negative x-axis, determine the magnitude of F1 and the orientation è ...

*September 1, 2014*

**Statics**

If both the projection Pa and component Fb of the force F are 305 N, determine the magnitude F and the orientation è of the b-axis. There is a 70 degree angle from the negative y-axis to the a-axis. There is a 108 degree angle from the negative y-axis to the force.

*September 1, 2014*

**Physics**

Determine the magnitude of the vector sum V=V1+V2 and the angle theta(x) which V makes counterclockwise from the positive x-axis. V1 = 34 units and makes a 20 degree angle with the +x axis V2 = 28 units and forms a 3,4,5 triangle with the -x axis

*August 27, 2014*

**Physics**

Determine the magnitude of the vector sum V=V1+V2 and the angle theta(x) which V makes counterclockwise from the positive x-axis. V1 = 34 units and makes a 20 degree angle with the +x axis V2 = 28 units and forms a 3,4,5 triangle with the -x axis

*August 26, 2014*

**biology**

Also the transmembrane protein functions as an ion and solute channel.

*August 21, 2014*

**biology**

You want to design an experiment to test if a bacteria affects a transmembrane protein. What types of controls should you use to eliminate effects of confounding variables?

*August 21, 2014*

**ALGEBRA**

A JAR CONTAINING 3 RED 4 BLUE AND 5 WHITE MARBLES WHATS THE CHANCE OF DRAWING FIRST A RED AND THEN WITHOUT REPLACEMENT A WHITE MARBLE?

*August 21, 2014*

**math**

thank you

*August 11, 2014*

**math**

How to write it in expanded form 12.0067 Is this answer right 1*10+2*1+6*1/1000+7*1/10000

*August 11, 2014*

**math**

How to write it in expanded form 12.0067 Is this answer right 1*10+2*1+6*1/1000+7*1/10000

*August 11, 2014*

**math**

How to write it in expanded form 12.0067

*August 11, 2014*

**Math**

Find an equation of the curve that satisfies the given conditions: (d^2y/dx^2)=6x, the line y=5-3x is tangent to the curve at x=1

*July 29, 2014*

**Math**

Suppose you own a tour bus and you book groups of 20 to 70 people for a day tour. the cost per person is $30 minus $0.25 for every ticket sold. Gas and other miscellaneous costs are $200. Part a) Write the revenue and cost functions for this situation Part b)Write the profit ...

*July 29, 2014*

**Calculus **

A container in the form of a right circular cone (vertex down) has a radius of 4m and height of 16m. If water is poured into the container at the constant rate of 16m^3/min, how fast is the water level rising when the water is 8m deep. V=(pi/3)(r^2)h

*July 27, 2014*

**calculus**

ddx(sin(x3)+(sin(x))3) =ddx(sin(x3))+ddx((sin(x))3) =3⋅(sin(x))2⋅ddx(sin(x))+cos(x3)⋅ddx(x3) =3x2⋅cos(x3)+3⋅cos(x)⋅(sin(x))2

*July 17, 2014*

**Math**

A container in the form of a right circular cone (vertex down) has a radius of 4m and height of 16m. If water is poured into the container at the constant rate of 16m^3/min, how fast is the water level rising when the water is 8m deep? V=(pi/)(r^2)h

*July 17, 2014*

**Chemistry **

For each of the following examples, decide whether it would be better to use the term molecule or formula unit. a. K2SO3 b. H2SO3 c. CCl4 d. NH4Cl

*June 5, 2014*

**Lake Arbor Elementary**

P=2w+2w

*June 3, 2014*

**Chemistry **

Complete and balance the reactions A) (CH3)2NH(aq)+CH3COOH(aq)→ B) CH3CH2NH2(aq)+HBr(aq)→ C) CH3NH2(aq)+HCOOH(aq)→

*June 3, 2014*

**Physics**

A 275-gram ball bounces off a wall. The ball stays in a horizontal plane throughout the motion. The ball strikes the wall with a speed of 4.50 m/s at an angle of 𝜃 = 35.0o relative to the wall and rebounds with the same speed at the same angle. If the ball is in ...

*May 27, 2014*

**geometry**

there exists a circle with chords. the chords are congruent. their corresponding arc measurements are 80 degrees and 2x+10 solve for x

*May 21, 2014*

**algebra**

5(2x-4)+ 11< 10 -2(6-x)

*May 20, 2014*

**Chemistry **

Free-energy change, ΔG∘, is related to cell potential, E∘, by the equation ΔG∘=−nFE∘ where n is the number of moles of electrons transferred and F=96,500C/(mol e−) is the Faraday constant. When E∘ is measured in volts, Δ...

*May 18, 2014*

**Chemistry **

Suppose a patient is given 140mg of I−131, a beta emitter with a half-life of 8.0 days. Assuming that none of the I−131 is eliminated from the person's body in the first 4.0 hours of treatment, what is the exposure (in Ci) during those first four hours? Express...

*May 14, 2014*

**Chemistry **

Suppose a patient is given 140mg of I−131, a beta emitter with a half-life of 8.0 days. Assuming that none of the I−131 is eliminated from the person's body in the first 4.0 hours of treatment, what is the exposure (in Ci) during those first four hours? Express...

*May 14, 2014*

**Physics**

A daredevil performs a stunt in which he jumps with his motorcycle from a horizontal cliff 10m high. What must the initial velocity of the motorcycle be, in order for the stuntman to barely clear a 10m wide water canal at the base of the cliff?

*May 8, 2014*

**Physics**

A little girl is standing on a cliff and throws a ball straight down at a speed of 5m/s towards the ground below. How far has it fallen 2.0 seconds after it leaves her hand?

*May 8, 2014*

**Physics**

A ball leaves a table with an initial horizontal velocity of 2.4m/s. The height of the table is adjustable. In two runs, the height of the table is set at 2.5m and 5.0m respectively. Assume air resistance is negligible. What is the horizontal distance between the two landing ...

*May 8, 2014*

**calculus help**

Find the derivative of the function. y = integral from cosx to sinx (ln(8+3v)) dv lower limit = cosx upper limit = sinx y'(x) = ????

*May 7, 2014*

**Physics/Calculus**

It takes a force of 21,714lb to compress a coil spring assembly on a New York City Transit Authority subway car from its height of 8in to its fully compressed height of 5in. A. What is the assemblys force constant? B. How much work does it take to compress the assembly the ...

*May 2, 2014*

**Calculus/Physics**

A spring has a natural length of 10in. An 800lb force stretches the spring to 14in. A. Find the force constant B. How much work is done in stretching the spring from 10 to 12 inches? C. How far beyond its natural length will a 1600lb force stretch the spring.

*May 2, 2014*

**Calculus/Physics **

It took 1800J of work to stretch a spring from its natural length of 2m to a length of 5m. Find the spring's force constant.

*May 2, 2014*

**science**

^ get rekt

*May 1, 2014*

**Physics MCQ - Quick check**

Thanks Damon

*April 28, 2014*

**Calculus**

The following are about an infinite region in the 1st quadrant between y=e^-x and the x-axis. B)Find the volume of the solid generated by revolving the region about the y-axis Part A was solved below. Does anyone know how to do Part B?

*April 27, 2014*

**Calculus**

Thank you. What about part B?

*April 27, 2014*

**Calculus**

The following are about an infinite region in the 1st quadrant between y=e^-x and the x-axis. A) Find the area of the region B)Find the volume of the solid generated by revolving the region about the y-axis

*April 27, 2014*

**Calculus**

Limit as x approaches 0 of x(1-cosx)/t-sinx. Confused on how to get this answer.

*April 21, 2014*

**Calculus **

Determine the behavior of limits A. Limit as x approaches 1 of: (log x)/((x-1)^2) B. Limit as x approaches infinity of: ((x-1)^2)/(log x))

*April 21, 2014*

**Calculus**

Thanks

*April 21, 2014*

**Calculus **

Evaluate limit as x approaches 0 of: csc^2(7x)tan(2x^2)

*April 21, 2014*

**CHEMISTRY HELP !!!! **

As a standard voltaic cell runs, it "discharges" and the cell potential decreases with time. Explain.

*April 19, 2014*