Tuesday

February 28, 2017
Total # Posts: 2,075

**Precalc**

Let x and y be real numbers such that x^2 + y^2 = 1. Find the max value of 2x - 5y. A hint was given to use Cauchy-Schwarz but I'm not sure how to apply it to vectors?

*June 7, 2016*

**Math**

Let a, b, and c be unit vectors, such that a+b+c=0. Show that the angle between any two of these vectors is 120 degrees. I proved this geometrically, but now my teacher wants a proof using vectors, and I don't know what to do.

*June 7, 2016*

**math**

How do you find P3, P13, and P15? P10 is obviously (-1, 0), but I'm not sure how you got P2 and how to find the other three points

*May 31, 2016*

**math**

Let P_1 P_2 ... P_18 be a regular 18-gon. Show that P_1 P_10, P_2 P_13, P_3 P_15 are concurrent. I've proved this with a diagram, but the question requires a rigorous proof.

*May 31, 2016*

**Math**

Suppose p and q are points on the unit circle such that the line through p and q intersects the real axis. Show if z is the point where this line intersects the real axis, then z=(p+q)/(pq+1) So far I've figured out that the equation for the line is z=p+t(q-p) but I don&#...

*May 31, 2016*

**math**

You deposit $400 in a savings account that earns 7% interest compounded annually. What is the function that represents your balance after t years?

*May 30, 2016*

**math**

Find the imaginary part of (cos(12) + i sin(12) + cos(48) + i sin(48))^6.

*May 28, 2016*

**Math**

Please help me with this ASAP! I need help with this just checking my answers thanks 1. There are 14 blue marbles, 8red marbles, and 12 green marbles in a jar. What is the ratio of the total number of marbles to the number of red marbles? A. 24:8 B. 34:8 (my answer) C. 8:34 D...

*May 26, 2016*

**Chemistry**

In a hydrogen- oxygen fuel cell hydrogen diffuses through the cathode. hydrogen and oxygen are mixed before entering the anode.*** oxygen diffuses through the anode. oxygen diffuses through the cathode.

*May 26, 2016*

**Chemistry**

To charge a lead storage battery you must apply a direct current to it. hold a magnet close to it.*** force alternating current through it. increase the pressure on it.

*May 26, 2016*

**ALGEBRA**

Rodney fa fair coin and chooses a ter tiles A, E, I, O AND U. He performs this experiment 50 times to determine the experimental probability that heds is tossed and the letter A is chosen. Whitch o following is st likely to be the experimental probability that Rodney ...

*May 23, 2016*

**Math**

If w^3 = 1 and w != 1, then compute (1 - w + w^2)(1 + w - w^2).

*May 21, 2016*

**Math**

Mike drank more than half te juice in his glass. What fraction of the juice could mike have drunk.

*May 18, 2016*

**science**

If Faraday hd used a more powerful battery in his experiments with electromagnetic induction, what affect would this have had on his galvanometer's measurements of current when the battery was fully connected? explain your reasoning. Thanks again!

*May 16, 2016*

**science**

Describe how turning off the electric current in an industrial magnet affects its magnetic field. Thanks!

*May 16, 2016*

**Math**

And yes I saw this problem on stackexchange but the solution was not very good at explaining it and only gave the math, which is really hard to understand

*May 6, 2016*

**Math**

Let z be a complex number, and let n be a positive integer such that z^n = (z + 1)^n = 1. Prove that n is divisible by 6. I have no idea how to approach this problem!

*May 6, 2016*

**science**

Lesson 9: Energy and the Environment Unit Test Science 7 B Unit 3: Energy and the Environment does anyone have answers to this text C.A

*May 4, 2016*

**Complex Numbers**

Let z and w be complex numbers such that |z| = |w| = 1, and zw is not equal to -1. Prove that (z + w)/(zw + 1) is a real number.

*April 28, 2016*

**Precalculus**

Let z and w be complex numbers such that |z| = |w| = 1, and zw is not equal to -1. Prove that (z + w)/(zw + 1) is a real number.

*April 27, 2016*

**Math**

Let z and w be complex numbers such that |z| = |w| = 1, and zw is not equal to -1. Prove that (z + w)/(zw + 1) is a real number.

*April 27, 2016*

**Complex Numbers**

Let z and w be complex numbers such that |z| = |w| = 1, and zw is not equal to -1. Prove that (z + w)/(zw + 1) is a real number.

*April 26, 2016*

**Polar, Cylindrical, and Spherical Coordinates**

Never mind, I think I get it now

*April 19, 2016*

**Polar, Cylindrical, and Spherical Coordinates**

Sorry, they just seem unclear, and you seem unsure of your final answer... And I didn't think you would respond to the original thread so I resposted

*April 19, 2016*

**Polar, Cylindrical, and Spherical Coordinates**

Let C be a circle that passes through the origin. Show that we can find real numbers s and t such that C is the graph of r = 2s*cos(theta + t) I think that I could start by writing it like R^2=(x-h)^2+(y-k)^2 where R is the radius of the circle, but I don't what to do with...

*April 19, 2016*

**math**

Find the probability of the following event: tossing a coin heads up or rolling a 3 with a number cube. I got: 1/2+1/6 = 2/3 but the right answer is 7/12. I don't understand how to get 7/12. Please help.

*April 18, 2016*

**Math**

tossing a coin tails up or rolling a number less than 4 on a number cube. I got 1/2 + 3/6 and got 1. The answer is 3/4. I don't understand what to do. Please help.

*April 18, 2016*

**Precalculus**

Let C be a circle that passes through the origin. Show that we can find real numbers s and t such that C is the graph of r = 2s*cos(theta + t) I think that I could start by writing it like R^2=(x-h)^2+(y-k)^2 where R is the radius of the circle, but I don't what to do with...

*April 18, 2016*

**Math**

Find the probability of the following event: tossing a coin tails up or rolling a number less than 4 on a number cube. I got 1/2 + 3/6 and got 1. The answer is 3/4. I don't understand what to do. Please help.

*April 18, 2016*

**Math**

Find the probability of the following event: tossing a coin heads up or rolling a 3 with a number cube. I got: 1/2+1/6 = 2/3 but the right answer is 7/12. I don't understand how to get 7/12. Please help.

*April 18, 2016*

**Math--Parametric Equations**

A hockey puck of diameter 3 inches is spinning around its center at a speed of 3 counterclockwise rotations per second. The center of the puck is traveling at a speed of 24 inches per second at an angle of 45 degrees to the positive x-axis. (a) At time t=0, the center of the ...

*April 15, 2016*

**Social Studies**

Are these right?

*April 12, 2016*

**Math: Trigonometry**

Find the sum of the three smallest positive values of x such that 4cos^2(2x-pi) = 3. (Answer in radians.)

*April 10, 2016*

**Math: Parametric Equations**

The graph of the parametric equations x=cos(t) y=sin(t) meets the graph of the parametric equations x=2+4cos(s) y=3+4sin(s) at two points. Find the slope of the line between these two points. So far I've set up the system of equations cos(t)=2+4cos(s) sin(t)=3+4sin(s) but ...

*April 10, 2016*

**Calculus**

An energy drink container in the shape of a right circular cylinder must have a volume of 12 fluid ounces (1 fluid ounce is approximately 1.80469 cubic inches). The cost per square inch of constructing the top and bottom is twice the cost of constructing the lateral side. Find...

*April 10, 2016*

**Math: Parametric Equations**

But that wouldn't be the right answer since it's asking for a length.

*April 9, 2016*

**Math: Parametric Equations**

So would the interval be (-inf, 1] ??

*April 9, 2016*

**Math: Parametric Equations**

Let G be the graph of the parametric equations x = cos(4t), y = sin(6t). What is the length of the smallest interval P such that the graph of these equations for all t E P produces the entire graph G? (The "E" represents the symbol for "is in" that looks ...

*April 9, 2016*

**Precalculus**

Oh I see! Yes, your answer is correct Reiny. Thanks!

*April 9, 2016*

**Precalculus**

Hmm 326 is not right... I'm also confused on "circumference = 8 (360/45) = 64 = 2 pi r" can you explain that a bit?

*April 9, 2016*

**Precalculus**

Points A, B, and C are on a circle such that angle ABC=45 degrees, AB=6, and AC=8. Find the area of the circle.

*April 9, 2016*

**Math: Trigonometry**

Does that mean there's 16 values of n?

*April 8, 2016*

**Math: Trigonometry**

For how many values of n with 0<=n<=100 is the graph of f(x) = sin(x + n) identical to the graph of g(x) = cos(x)? I think that I should use the relationship that cos(x)=sin(90-x) but I'm not sure how.

*April 8, 2016*

**Trigonometry**

For how many values of x such that 0<x<360 do we have cos(x) = 0.1? (x is in radians)

*April 5, 2016*

**Trigonometry**

If sin(x) = 4cos(x), then what is (sin(x))*(cos (x))?

*April 4, 2016*

**Math**

You order a pizza. The pizza has a diameter of 14 inches and it is cut into 12 equal slices. You eat four slices, how much of the area have you consumed. How long is the remaining crust.

*March 27, 2016*

**English**

Its on "Lamb to the Slaughter" and "Royal Jelly", both by Roald Dahl.

*March 21, 2016*

**English**

Would someone be willing to grade or check my rough draft of a critical review?

*March 21, 2016*

**Algebra**

Find ALL triples of positive numbers c<100 that satisfy the Pythagorean Theorem.

*March 14, 2016*

**biology**

what type of cell recognizes cells that have been infected by viruses because the infected cells have viral proteins on their surfaces?

*March 13, 2016*

**geometry**

an inscribed angle with a diameter as a side has a measure of x degrees. if the ratio of measure of arc AD to measure of arc DB is 1:4, what is the measure of arc DB?

*March 7, 2016*

**geometry**

A painter sets a ladder up to reach the bottom of a second-story window 16 feet above the ground. The base of the ladder is 12 feet from the house. While the painter mixes the paint, a neighbor's dog bumps the ladder, which moves the base 2 feet farther away from the house...

*February 28, 2016*

**Algebra**

No, not in calculus yet - I will take that next. Thank you so much for your help!

*February 28, 2016*

**Algebra**

A rectangular playground is to be fenced off and divided in two by another fence parallel to one side of the playground. 440 feet of fencing is used. Find the dimensions of the playground that maximize the total enclosed area. Remember to reduce any fractions and simplify your...

*February 28, 2016*

**science**

Yeah it's C 100%

*February 18, 2016*

**Pre-Calc**

Solve the quadratic equation by factoring. Check your solutions in the original equation. (Enter your answers as a comma-separated list.) x^2 + 2ax + a^2 = 0

*February 11, 2016*

**Math**

An open gift box is to be made from a square piece of material by cutting four-centimeter squares from each corner and turning up the sides (see figure). The volume of the finished gift box is to be 324 cubic centimeters. Find the size of the original piece of material.

*February 11, 2016*

**Pre-Calc**

An open gift box is to be made from a square piece of material by cutting four-centimeter squares from each corner and turning up the sides (see figure). The volume of the finished gift box is to be 324 cubic centimeters. Find the size of the original piece of material.

*February 11, 2016*

**nursing**

1 L is to infuse every 12 hours. calculate the mL/hr

*February 10, 2016*

**Math**

Never mind. My mom helped me.

*February 8, 2016*

**Math**

Which equation has a slope of -1/2 and a y intercept of -3? a. 4x+2y+3=0 b. 3x+6y+6=0 c. 5x +10y+30=0 d. 6x+2y+1=0 I have the answer. I know it is C, but this was today's lesson and I still don't understand why or how to get C. Please help.

*February 8, 2016*

**math**

the product of y and six exceeds three times the sum of y and four

*February 7, 2016*

**Chemistry**

Kc = 28 at some temperature for the reaction H2(g) + I2(g) ⇀↽ 2 HI(g). If 16.7 moles of HI are introduced into a 10.0 liter vessel, how many moles of I2 are present at equilibrium? Answer in units of mol.

*February 2, 2016*

**Chemistry**

The heat of vaporization of water is 9.73 kcal/mol. At what pressure (in torr) would pure water boil at 89◦C?

*February 2, 2016*

**Math Please check**

(1/8)17n x 8 I got: 17n/8 x 8= 17n not sure about this??

*February 2, 2016*

**Math**

Yes that's what I meant. Thank you

*February 2, 2016*

**Math**

4s-(3-2s)-6=9 Please check my work: 4s-3+2s-6=9 6s-9=9 3s=18 s=3

*February 2, 2016*

**math**

The probability of drawing a red coin after three blue coins are put in the bag to replace the red one that has been removed is

*February 2, 2016*

**Math**

Could you please explain the differences between linear relationships and exponential relationships? How or when would I use either or them? Thank you.

*February 1, 2016*

**Math**

The area of a rectangle is 12 square feet. What are all the possible integer values of its perimeter? I got: 1. all sides equal to 3 2. 5, 5, 1, 1 3. 4,4,2,2 Did I miss any combinations?

*January 30, 2016*

**Math**

A rollercoaster travels at 120 miles per hour on its track for 3 minutes. A. 3 minutes is what part of an hour? B Use a formula and your answer from above to calculate the distance traveled. A. I got 1/20 or 5% B. Not sure what formula to use. But I got .40 of a mile What do ...

*January 30, 2016*

**Math**

Got it now! Thank you!

*January 28, 2016*

**Math**

49^2 is 2,401 is that the area of the tablecloth? The back of my book has the answer as 2704, did I forget to do something?

*January 28, 2016*

**Math**

A square table has an area of 2116 square inches. A tablecloth hangs 3 inches over each end of the table. a. What is the length of one side of the table? b.What is the area of the tablecloth? a. I know is 46 inches Please help me to figure out b. Thank you.

*January 28, 2016*

**Algebra**

Thank you!

*January 27, 2016*

**Algebra**

I just need help setting up the equation - the rest I can do on my own: A man built a walk of uniform width around a rectangular pool. If the area of the walk is 253 square feet and the dimensions of the pool are 9 feet by 3 feet, how wide is the walk?

*January 27, 2016*

**language Arts**

In the excerpt from Barrio Boy, what makes Ernesto similar to several of his classmates?

*January 25, 2016*

**English**

Thanks James :)

*January 24, 2016*

**English**

THANK YOU AUSTRALLIAN DUDE! OMG I GOT THEM ALL RIGHT (Exept for one but that's okay your awesome 16 was really theirs.) Thanks again!! :)))

*January 24, 2016*

**Math**

A can containing 3 tennis balls has a volume of 128/9pi cubic inches. If the height of the cylinder is 8in., what is the diameter of each tennis ball. Please explain how to do this.

*January 21, 2016*

**Math**

Mary bought a roll of ribbon. After using 5/8 of the ribbon to decorate some packages she had 15ft left how many feet of ribbon did she buy

*January 20, 2016*

**PHYSICS**

In your moving car, you covered 2.0 m during the first 1.0 s, 4.0 m during the second 1.0 s, 6.0 m during the third 1.0 s, and so forth. Find the acceleration.

*January 13, 2016*

**Poetry**

Jadore is right thank you!!! <3333

*January 12, 2016*

**Math**

Thank you! 21y 21 X 42= 882 I get it! Thank you!

*January 12, 2016*

**Math**

An orchard has enough space to plant 21 rows with y trees in each row, or 18 rows with y+7 trees in each row. If each orchard plan contains the same number of trees, how many trees can each orchard contain? *I know the answer is 882 trees. But, I have no idea how to set up the...

*January 12, 2016*

**Algebra**

Thanks Damon I tool all the notes on the lessons that they gave me I just counldnt figure out what to do because all of the examples didn't have this kind of formula. Thanks again

*January 8, 2016*

**Physics**

Then air exerts a forward force of 8 N on the propeller of a 0.25 kg model airplane. If the plane accelerates forward at 1.8 m/s^2, what is the magnitude of the resistive force exerted by the air on the airplane? Answer in units of N.

*January 7, 2016*

**4 grade division**

Do you mean 368/6? 6x6=36 with zero left over, next step, Bring down the 8 6 goes into 8 one time with 2 left over so 61 r2

*December 24, 2015*

**Physics**

The driver of a car is going 30 m/s slams on his brakes, the car's tires lock, and the car skids to a stop on a level roadway. The kinetic coefficient of friction between its tires and the pavement is 0.75 as it slides. Draw a free body diagram of the car, find its ...

*December 22, 2015*

**math**

OK what?

*December 17, 2015*

**math**

Write an equation with a variable on both sides of the equal sign that has infinitely many solutions. Solve the equation and explain why it has an infinite number of solutions. I have no idea?

*December 17, 2015*

**math help plz?**

Ok thank ya'll so much. :)

*December 17, 2015*

**math help plz?**

So its D?

*December 17, 2015*

**gRammar**

True

*December 14, 2015*

**Math**

Ok, I get it now. Thank you.

*December 5, 2015*

**Math**

The length of a rectangle is 5 inches less than 3 times the width. The perimeter of the rectangle is 14 inches. Find the length and width of the rectangle. I did this: Length 3x-5; width 3x Then I did guess and check and came up with X=2 solving the problem with a perimeter of...

*December 5, 2015*

**Math**

Jim uses ribbion to make bookmarks. Jim has 9 feet of ribbion. He uses 1/3 foot of ribbon to make each bookmark. What is the total number of bookmarks J makes with all 9 ft of ribbon?

*November 29, 2015*

**math**

Maybe they are asking how much was added to get 4.87? Then you would subtract 4.87 and 3.93 to see how much was added.

*November 29, 2015*

**Math**

Yay! Thank you!

*November 28, 2015*

**Math**

I found x=4 and y=8 is that right? Then I found the area is 16. Is that right?

*November 28, 2015*