Sunday

November 29, 2015
Total # Posts: 35,840

**Algebra 2**

-4|t-2| - 9 = -37 -4|t-2| = -28 |t-2| = 7 so, which numbers are 7 away from 2? t = 9 or -5 more rigorously, either (t-2) = 7 t=9 or -(t-2) = 7 -t+2 = 7 t = -5
*October 27, 2015*

**precalc**

clearly 2x = pi/6 tan(x+pi/2) = -cot(x) 3sec(x-pi/4) = 6 sec(x-pi/4) = 2 cos(x-pi/4) = 1/2 x-pi/4 = pi/3 now just look in all the quadrants that work.
*October 27, 2015*

**Math**

agree an even multiple of any integer is always even
*October 27, 2015*

**Math**

assuming you mean y=2log_5(x)-7 reflected it is y = -2log_5(x)+7 shifting up you just add 6: y = -2log_5(x)+13
*October 27, 2015*

**calculus**

correct
*October 27, 2015*

**Math**

add 'em up and divide by 4.
*October 27, 2015*

**Maths**

seems pretty clear to me. Just double all the numbers.
*October 27, 2015*

**Math**

so, use the formulas - what's the problem?
*October 27, 2015*

**Precalc**

3s+c = 71 a = √3/4s^2 + c = √3/4 s^2 -3s + 71 da/ds = √3/2 s - 3 clearly a is minimum when s = 2√3 so, the circumference c is 71-6√3
*October 27, 2015*

**science**

distance = speed * time
*October 27, 2015*

**Federal polytechnic, oko**

a = (104m/s)/(10s) = 10.4 m/s^2 F = ma now go for it.
*October 27, 2015*

**Maths**

type in your function at wolframalpha.com
*October 27, 2015*

**11 Grade Math-Based Physics**

#1 Lose the apostrophes 1a, 1b look good 1c cannot be right, since m/s is not acceleration. #2 all ok #3 is (a) - speed has no direction. (c) is for velocity #4. Not sure what 60° NE means. I know N 60° E and E 60° N. In any case, draw the direction and take the ...
*October 27, 2015*

**physics**

find the speed of sound. If it is x m/s, then you have two equal distances. The distance fallen is s = 5t^2, so the falling time is √(s/5) The sound takes s/x seconds to come back. √(s/5) + s/x = 3 So, look up x and do the math for s, the well depth. The rest then ...
*October 27, 2015*

**Math**

((6/7)/2)/3 = 1/7
*October 27, 2015*

**PHYSICS**

As always, draw a diagram. use the law of sines AC/sin50° = 100/sin70°
*October 27, 2015*

**maths 3 advanced**

ignoring all those pesky zeros, we can set up the ellipse as follows: center of earth at (0,0) perigee at (-8,0) apogee at (16,0) center at (4,0) so, the equation is (x-4)^2/a^2 + y^2/b^2 = 1 plugging in our points, we have 144/a^2 + 0 = 1 a = 12 a^2-c^2 = b^2 b^2 = 12^-4^2 = ...
*October 27, 2015*

**maths**

500 what? pages? seconds? How about asking an actual question instead of just mumbling at the end?
*October 27, 2015*

**Physics**

It sounds like you mean period ∝ L^(3/5) v ∝ L/T = L/L^(3/5) = L^(2/5)
*October 27, 2015*

**Math 3**

y = 1/21 (x-3)^2 (x+7) y' = 1/21 (x-3)(3x+11) That help?
*October 27, 2015*

**physics**

find t when h=0. h(t) = 95+10t-4.9t^2
*October 26, 2015*

**Geometry**

well, you give no relationship among the angles, but one possible avenue is to assume that 2x + x-5 = 100
*October 26, 2015*

**Math**

it hasn't been simplified at all. You did, however, correctly apply the distributive property to remove the parentheses. Many people consider factoring out common values to be simplification. In that case, I'd have to say that factoring out another p, giving 2p^2q(3-q^...
*October 26, 2015*

**Math**

your question kind of got garbled on the way. I can tell you that the speed of a point on the wheel is 60πcm/rev * 5rev/s = 300π cm/s do with that what you will
*October 26, 2015*

**math**

between $1000 and $2000 1xxx a multiple of 10 1xx0 hundreds digit is 30 times the value of the tens digit 1620 ..40 not possible, or 30x would be too big
*October 26, 2015*

**CALCULUS TEST TOMORROW**

well, just do the math 1/R = 1/R1 + 1/R2 plug in R1 and R2 to find R 1/R^2 dR/dt = 1/R1^2 dR1/dt + 1/R2^2 dR2/dt Now just plug in your numbers to find dR/dt
*October 26, 2015*

**Calculus**

∫[0,1] ∫[-√(x-x^2),√(x-x^2)] √(x^2+y^2) dy dx Or, you might find things easier in polar coordinates.
*October 26, 2015*

**algebra**

where did you get 300W? If there are two short sides (x) and one long side (y), then 2x+y = 300 a = xy = x(300-2x) = 10450 Now solve that for x, the short side.
*October 26, 2015*

**Calculus plz help integral**

It appears you want ∫[0,1/2] √x e^x dx if you let x = u^2 dx = 2u du then you have ∫[0,1/√2] u e^(u^2) * 2u du = 2∫[0,1/√2] u^2 e^(u^2) du Hmmm. Not much better. These involve the err function, so unless you have a table of that handy, you&#...
*October 26, 2015*

**Calculus help**

x^(1/3) + (xy)^(1/3) = 4y^2 1/3 x^(-2/3) + 1/3 (xy)^(-2/3) (y + xy') = 8yy' Now just solve that for y'. There are several ways to massage the final answer.
*October 26, 2015*

**Math**

#5. ok #6. ok #7. ok, assuming a typo in the question. #8. ok
*October 26, 2015*

**algebra**

Can you solve q = p(5) for p?? If so, do the same step for this one.
*October 26, 2015*

**Geometry Rectangle**

With two short sides (x) and one long side y, 2x+y = 100 The area is a = xy = x(100-2x) So, you just need to solve x(100-2x) = 1200 2x^2-100x+1200 = 0 2(x-20)(x-30) = 0 now can you figure it out?
*October 26, 2015*

**Math 1350**

If BC is x, then 2x + x + x+10 = 58 x = 12 AC = AB+BC = 2x+x = 36
*October 26, 2015*

**Geometry:Rectangles**

If the width is x, then the length is 100-2x. SO, the area is x(100-2x) = 1200 2x^2 - 100x + 1200 = 0 x^2 - 50x + 600 = 0 ...
*October 26, 2015*

**Math**

wow. That's some mistyping of "like terms in"! There are two y terms, so (A)
*October 26, 2015*

**math**

well, two sides are x and x+2 I have no idea what half of the sum of the longest side might mean. A sum involves the addition of two numbers.
*October 26, 2015*

**Math**

nope. That's the only certainly wrong choice. So, given that one of the other three is correct, which one is it?
*October 26, 2015*

**Math**

3.50 n >= 140.00
*October 26, 2015*

**Treasure!**

Look in Mt Doom. It's right next to the One Ring!
*October 26, 2015*

**maths**

clearly, x=1 and y=1 is a solution. It is clearly the only solution, since using any other natural numbers (which are positive integers) produces 2x+5y which is greater than 7. If you include all real numbers, the graph is a line, and any point on the line is a solution. It ...
*October 26, 2015*

**Precalculus**

I assume you can find the normal trig angle associated with the point. For an angle θ, measured clockwise, the bearing is 90+θ. Just plot the point and note how many degrees clockwise from vertical it is. That is the compass heading.
*October 26, 2015*

**math**

clearly the ratio of each smaller square is 1/√2. So, you have a geometric progression with a = 8 r = 1/√2 Now just apply your formulas for the sum of such a sequence.
*October 25, 2015*

**Calculus**

If the final box has bases x^2 and height h, then v = x^2 h and we also have x^2 + 4xh = 100, so h = (100-x^2)/4x That means v = x^2 (100-x^2)/4x = x/4 (100-x^2) = 25x - 1/4 x^3 dv/dx = 25 - 3/4 x^2 maximum volume is achieved when dv/dx=0.
*October 25, 2015*

**Calculus**

divide the fencing equally among lengths and widths.
*October 25, 2015*

**Algebra 2**

so, did you make a graph?
*October 25, 2015*

**Calculus**

google is your friend. lots of examples online. you looking for solids of revolution, or 3D volumes in general?
*October 25, 2015*

**Calculus @Damon**

oh yeah - Good catch
*October 25, 2015*

**Calculus**

consider the population as a collection of rings of thickness dr. Each ring's population is the area of the ring times its density. Add them all up and you get p(r) = ∫[0,7] 2πr*5(5+r^2)^(1/3) dr for the insects, dp/dt = 280 + 8t + 1.5 t^2 p(t) = 40 + 280t + 4t^...
*October 25, 2015*

**Math**

if he starts at (0,0), then he winds up at (8,4). So, he is then √80 miles from home.
*October 25, 2015*

**math**

well, 2/3 = 0.66666 which is greater than any of the other numbers I have no idea what the desired inequality is supposed to be.
*October 25, 2015*

**words problems**

the two plans are modeled by a = 20+0.12x b = 65 now do with that what you will
*October 25, 2015*

**Math**

well, just remember that sin = y/r cos = x/r sin u cannot be negative if u is in QII. Anyway, just recall your common triangles: 5-12-13 and 3-4-5. Draw them in the proper quadrant and find the missing side. Then just plug the numbers into your difference formula for cosine.
*October 25, 2015*

**Math Answer Check**

Hmmm. I get -(√2+√6)/4 Better check your +- signs.
*October 25, 2015*

**probabilities**

1/26 * 1/25 * 1/24 * 1/23 = 22!/26!
*October 25, 2015*

**Calculus**

They did not say that f(x) = 12x They said that the area was 12. The integral was already done for you.
*October 25, 2015*

**algebra**

how do you figure "how many times" one number is? You divide? How many times as big as 20 is 100? 100/20 = 5 So, just divide sunmass/jupitermass The trick is: can you divide numbers in scientific notation? Review your text for examples.
*October 25, 2015*

**math**

well, your danger sign is that you got a negative answer. If a > b, a-b > 0. In fact, you read the question backwards. How much bigger than 4 is 10? 10-4, not 4-10.
*October 25, 2015*

**math**

if x is at 4%, then the rest (25000-x) is at 7% So, add up the interest: .04x + .07(25000-x) = 1450
*October 25, 2015*

**geometry**

pick any height h. Then the base has area 192/h. Then devise a triangle with that area. If you want integers, note that 192 = 3*2^6
*October 25, 2015*

**Algebra 1**

A set of n elements has only 2^n subsets. B has a duplicate set listed. The order of elements in a set is not important. C is the answer.
*October 25, 2015*

**math**

(75.00/48.99)*51.93
*October 25, 2015*

**math**

thesameasforanyothernumber -- 1/6
*October 25, 2015*

**Math**

yes.
*October 25, 2015*

**math**

the distance from the line to the point is |5*3+12*4+11|/√(5^2+12^2) = 74/13 So, now you know the center and the radius. Just write the equation. see the graphs at http://www.wolframalpha.com/input/?i=plot+5x%2B12y%2B11%3D0%2C+%28x-3%29^2%2B%28y-4%29^2+%3D+%2874%2F13%29^2
*October 25, 2015*

**Trigonometry**

poke around a bit and you will find proofs that if the tangents intersect at an angle θ, then if the circles have radii r and R, and the centers are d apart, then sinθ = √(2r^2R^2 + 2r^2d^2 + 2R^2d^2 - r^4 - R^4 - d^4)/(2Rr) so, plug in your numbers
*October 24, 2015*

**MATH**

(−2x^−3 y^−2 )^−1 = -1/2 x^3 y^2 1/(x^3y^3z^3 )^−4 = x^12 y^12 z^12 now multiply and you get -1/2 x^15 y^14 z^12
*October 24, 2015*

**astronomy**

(4*10^33) / 4π(2*7*10^10)^2 = 3/(4π*4*7^2) * 10^13 = 0.001218 * 10^12 = 1.218 * 10^9 You plugged in the radius, not the diameter.
*October 24, 2015*

**Physics**

a = (42.3/13.8) m/s^2 weight is now 70.2(g+a)
*October 24, 2015*

**trignometry**

graphs can be done at wolframalpha.com or many other sites.
*October 24, 2015*

**trignometry**

your equation is (2cos4θ - 1)(cos4θ + 3) = 0 so, find all the angles θ where cos4θ = 1/2 or cos4θ = -3 Note that cos4θ has period pi/2, so you will have more solutions than normal, since the domain covers 4 periods.
*October 24, 2015*

**trignometry**

sinx (1+2cosx) 0 so, sinx = 0 or cosx = -1/2
*October 24, 2015*

**trigonometry**

putting everything i nterms of sin and cos, you have 2sinx + cosx/sinx - 1/sinx = 0 (2sin^2 x + cosx - 1)/sinx = 0 so, x where sinx=0 must be excluded from the domain. (2 - 2cos^2 x + cosx - 1) = 0 2cos^2 x - cosx - 1 = 0 (2cosx + 1)(cosx - 1) = 0 so, you need cosx = -1/2 or ...
*October 24, 2015*

**Pre- Algebra**

what is the difference between 10 and 5? same thing here.
*October 24, 2015*

**Qibing**

tax benefits
*October 24, 2015*

**addition fraction**

use a common denominator of 60 and then add 'em up.
*October 24, 2015*

**AP Physics**

the trajectory article at wikipedia gives a good discussion of this kind of problem.
*October 24, 2015*

**math**

13 cards in each suit. 1st card has to be some suit. Given that, P(same,same) = 12/51 * 11/50
*October 24, 2015*

**epcc**

0.80 of course. Now, if you want the mass, that is 0.8 * (molar mass of compound) Add up all the atomic masses involved in the molecule to get the molar mass.
*October 24, 2015*

**physics**

see the wikipedia entry for trajectory for a good discussion.
*October 24, 2015*

**Physics**

Since F=ma, the 0.2N friction causes a deceleration of .2/.03 = 1.67 m/s^2 so, its speed and position are described by v = 36 - 1.67t s = 36t - 0.83 t^2 You can find t when v=0 (stopped) and use that value to find the stopping position. Not uniform motion, but uniform ...
*October 24, 2015*

**MATH - sheesh!**

surely a calculator is quicker than posting and waiting. Just saying...
*October 24, 2015*

**math**

dN = .03N dt you have N=100 and dt=0.1 plug and chug N(4.1) ≈ 100 + dN
*October 24, 2015*

**C++programming**

I must say, you got a lotta nerve. Don't expect anyone to write this for you. But we will take a look at what you have. On the other hand, the compiler will do that for you, and simply running your code will verify its function. A bare-bones version of this cannot be more ...
*October 24, 2015*

**use auxilary verb in bracket**

i do wish to take a break. i'm so tired.
*October 24, 2015*

**math**

the 2nd line says that a^2+b^2 = 5ab a^4+b^4 = (a^2+b^2)^2 - (2ab)^2 That should help, but I cannot decipher the ~A character. Go for it.
*October 24, 2015*

**Calculus 1**

f(0) = 0 f(16) = 4 slope of secant: 1/4 f' = 1/2√x 1/2√x = 1/4 2√x = 4 x = 4 which is in [0,16] verify at http://www.wolframalpha.com/input/?i=plot+y%3D%E2%88%9Ax%2C+y+%3D+%281%2F4%29%28x-4%29+%2B+2+for+0+%3C%3D+x+%3C%3D+16
*October 24, 2015*

**Math**

product of a number and six: 6x 6 decreased by n is 6-n, so you wind up with 6 - 6x = 20
*October 24, 2015*

**math**

if the mean was 50, then the total was 100*50 Now, the mean is (100*50 + 10)/50 = 50.2 The median is the same, since the place of the middle value has not changed. This must be so, since it is less than 100, and only the greatest value has changed.
*October 23, 2015*

**Math**

that's better
*October 23, 2015*

**Math**

cannot be. |sin(x)| <= 1 for any x. 7pi/6 - pi/3 = 2pi/3 so, what is sin(2pi/3) = sin(pi/3) ?
*October 23, 2015*

**Math**

of course not. If 1-u = 1, then u=0. Unless one of those tan values is zero, the assertion is false.
*October 23, 2015*

**Algebra**

For x ft^2 of wall, you want 4*30 + 1.10x < 4*24 + 1.20x
*October 23, 2015*

**Trigonometry**

Draw a diagram. If the tip of the shadow is x feet horizontally away from the tree of height x, we have x/31 = cos 7° (h + 31*sin7°)/x = tan 59° I get h = 47.4 ft
*October 23, 2015*

**Algebra 2**

no. You just keep multiplying by 1/2.
*October 23, 2015*

**Math**

use your calculator. sin 26.56° = 1/√5 Use your arcsin or sin^-1 button. Or use an online calculator.
*October 23, 2015*

**Math**

you know that if v is the initial upward velocity, v-9.8*0.67 = 0 Plug that into the usual equation h(t) = 88 + 6.566t - 4.9t^2 Then check that h(3.18) = 0 Or, since a parabola is symmetric, you know that h(t) = a(t-0.67)^2 + 88 h(3.18) = 0, so a(3.18-0.67)^2 + 88 = 0 h(t) = -...
*October 23, 2015*

**Math**

plug in some values. After 5 steps, you will have 5 equations, which you can then solve as usual. For example, if x=3, 81a+27b+9c+3d+e = 6 and so on.
*October 23, 2015*

**Math**

well, g'=4x^3-15x^2+14x-3 where is g'=0?
*October 23, 2015*

**shahabdulatif science**

clearly, the acceleration is ((20-10)m/s)/((5-0)s) = 10/5 = 2 m/s^2 so at t-3, v = 10-3*2 = 4 m/s
*October 23, 2015*