Monday

October 24, 2016
Total # Posts: 45,212

**math**

you ask us to show our work in solving the problem. Why not show your work and how it went wrong? I suspect a typo, since 5(0) - 10 = -5 That makes your equation 2(3x-6) = -5 So, does -5 work? 2(3(-5)-6) = 2(-15-6) = 2(-21) = -42 Nope. Now you try the others to see whether any...

*September 20, 2016*

**Math**

fifty seven million three hundred seventy-three thousand two hundred eighty-four = 57373284 Now just move the decimal place as needed.

*September 20, 2016*

**Algerbra**

well, 1.7x10^2 = 0.17x10^3 Now just add 'em up

*September 20, 2016*

**Math**

review the conditions for the series to exist. In this case, it will exist for x=0, so we want y = ∑anx^n y' = ∑nanx^(n-1) y" = ∑n(n-1)anx^(n-2) The DE then says ∑n(n-1)anx^(n-2) + x*∑nanx^(n-1) + ∑anx^n = 0 ∑n(n-1)anx^(n-2...

*September 20, 2016*

**math - eh?**

You want to try that again in English?

*September 20, 2016*

**Math Question**

why are there 4 empty squares? Or are some of the numbers used more than once?

*September 20, 2016*

**maths**

c+s+h = 100 5c + s/10 + 2h = 100 There is no unique solution if that is all you are given. And the plural of sheep is sheep, not sheeps, and certainly not sheep's!

*September 20, 2016*

**Math**

just multiply 5 by the desired value(s)

*September 20, 2016*

**physics**

no friction means no force no force means no acceleration no acceleration means constant velocity.

*September 20, 2016*

**maths calculus need help plz**

this is a pretty standard linear DE. Read about its method of solution here: https://answers.yahoo.com/question/index?qid=20120112065721AA0UzfI If you're still confused, there are lots of explanations on why the method works so well.

*September 20, 2016*

**Math**

recall that the angles of a triangle sum to 180°. So, you must have 2x+5 + 6x-5 + 7x = 180

*September 20, 2016*

**ALGEBRA**

(212-32) = 180 SO, there are 180°F for 100°C So each °F is 5/9 as big as a °C each °C is 9/5 as big as a °F That should help you get started.

*September 20, 2016*

**Math**

really? How many times larger is 20 than 4? How did you get that answer? Do the same thing for your numbers. Remember that you divide the values and subtract the powers. What do you get?

*September 20, 2016*

**Matg**

Luckily, the 3' width of the rolls divides either dimension of the room, so you don't have to worry about buying extra rolls for the leftover width. Carpet Master: (720*30 ft^2) * 1roll/6ft^2 * $1/roll = (720*30*1/6*1) = $3600 Flooring King: (720*30 ft^2) * 1roll/36ft^...

*September 20, 2016*

**physics**

oops: watch the units (66.4km/hr) / (t hr) = 66.4/t km/hr^2 I'd say: total distance: 99.5(t - 24/60) avg speed = distance/time 99.5(t - 24/60)/t = 66.4 t = 1.202 distance is thus 99.5(1.202 - 24/60) = 79.8 km

*September 20, 2016*

**Maths Constructions**

you can construct a right angle by making a perpendicular bisector of a line segment. That's one of the very first constructions you did. Mark the right angle as point B. Then, mark off side BA. Then from A, set the radius to 6.2cm and draw an arc that intersects the ...

*September 20, 2016*

**Math**

Let C = {4,5} Then A = {2,C,4} They are all incorrect, and it should be clear why. What are your reasons?

*September 20, 2016*

**Algebra**

since distance = speed * time, (s-50)(5) = (s+50)(4.5) That's some fast plane!

*September 20, 2016*

**Precalculus**

For the inside argument, the domain is all real numbers except where the denominator is zero. If your denominator is -x^2-4x-10 it is never zero, since the discriminant is 16-40 < 0 So, the domain is (-∞,∞) Now, for the log to be defined, we need 10+|x+6|/(-x^2-...

*September 20, 2016*

**Algebra**

g = b+16 g+13 = 2(b+13) now just solve for g and b.

*September 20, 2016*

**math**

no, 2+2 = 4

*September 20, 2016*

**science**

Since PV=kT, PV/T is constant. So, you want T where (1.41)(25.1)/T = (1.82)(18.7)/353

*September 19, 2016*

**Calculus**

yes, k=2

*September 19, 2016*

**Pre algebra**

-12/(3(-8+(-4)^2-6)+2) -12/(3(-8+16-6)+2) -12/(3(2)+2) -12/8 -3/2

*September 19, 2016*

**Math**

Do you mean 8*4^(2x) - 4 = 53 8*4^(2x-4) = 53 either way, isolate the 4^? and then take log of both sides to get x by itself on the left.

*September 19, 2016*

**math**

a. The power of an electric appliance is given by the formula P=I^2R, where I is the current and R is resistance. Use this information to explain how you can use radicals to determine the current if the power and the resistance is given. b. Find the current in amperes if a 40-...

*September 19, 2016*

**MATH**

can't see, but I'd bet that it's √2 times the value shown.

*September 19, 2016*

**Math please help**

It does not matter! Pick any number you like. Just be sure to use it both top and bottom. I know you have trouble with math, but I was hoping you could understand English...

*September 19, 2016*

**Math please help**

starting with 5/6, multiply both top and bottom by the same number, such as 3: 5/6 = 15/18 Now fill in the other blanks.

*September 19, 2016*

**Grade 10 Math**

As always, draw a diagram. She is standing 3 ft from where the wire is attached to the ground. Using similar triangles (in inches), the height h can be found by 69/36 = h/180

*September 19, 2016*

**Algebra**

Ab^2 = -18 A(3^(1/5))^2 = -18 A(3(2/5)) = -18 A = -18 * 3^(-2/5) = 18 / 9^(1/5) = 2 * 9^(4/5) It would be nice if you showed your work ...

*September 19, 2016*

**Algebra**

Ab^-3 = -6 Ab^2 = -18 divide to get rid of the A's and you have b^-5 = 1/3 b^5 = 3 b = 3^(1/5) Now use that to get A

*September 19, 2016*

**math**

24 = 8*3 32 = 8*4

*September 19, 2016*

**Physics**

how long does it take a penny to rise and fall, starting at 3.0 m/s? v = 3 - 9.8t double that, and that's how long the first penny has been dropping before the 2nd gets back to the top of the well.

*September 19, 2016*

**algebra**

since you are given a point and a slope, start with the point-slope form: y-5 = 3(x-1) Now just rearrange things to get what you need.

*September 19, 2016*

**Algebra**

I don't know whether you worked it right, since you didn't show what you did, but you got the right answer

*September 19, 2016*

**Math**

ummm, 300/10 = ?

*September 19, 2016*

**math**

1,60 2,30 ... Consider the factors of 60. It should not take long to fine the right ones.

*September 19, 2016*

**Math**

did you try listing the first few? The pattern should be clear 1 = 1 1+3 = 4 1+3+5 = 9 1+3+5+7 = 16 Does the sequence 1,4,9,16,25,36,... look familiar?

*September 19, 2016*

**sciences**

first, decide which are acids, and which are bases. Then, what does the litmus paper do in each case?

*September 19, 2016*

**Algebra**

y=3x-7 That may not be the one you want, however. Try n=making your own, considering that cost = flat_fee + rate * time

*September 19, 2016*

**math**

one connects two equal things, the other describes how they are unequal. equation vs inequality

*September 19, 2016*

**Math**

v = π*25*3 as for the time, check the units: (cm^3) / (cm^3/min) = min

*September 19, 2016*

**Math**

change all the fractions to decimals and compare them

*September 19, 2016*

**Math**

well, 2720/6 = 453 2/6

*September 19, 2016*

**physics**

balance momentum: .020 * 150 = 2v

*September 19, 2016*

**maths trignometry**

I assume you mean √((seca + 2sina)/(seca-2sina)) = (sina+cosa)/(sina-cosa) well, clearly, the first thing to do is square both sides: (seca + 2sina)/(seca-2sina) = [(1+2sina*cosa)/cosa] / [(1-2sina*cosa)/cosa] = (1+sin2a)/(1-sin2a) see where that takes you, after ...

*September 19, 2016*

**Math, please help! :)**

Ms. Sue has a point. The list will have to be 5, 9, 12, x, 13, 17 or 5, 9, 12, 13, x, 17 Since there are six number, the median will be the average of the middle two. (12+16)/2 = 14 but 16 cannot be inserted in between 12 and 13, and if it goes after 13, then the median is 12.5

*September 19, 2016*

**algebra - theory of numbers**

google is your friend. You might want to start here: https://en.wikipedia.org/wiki/Divisor_function

*September 19, 2016*

**Trigonometry**

But anyway, if arctan(2) is the solution to a problem, just leave it as-is. That way you have the exact answer, instead of just an approximation. And, it's clear what the value is. Saying that θ = 1.107 does not give much insight into where it came from.

*September 19, 2016*

**Trigonometry**

short answer: no you can always use graphical or numeric methods to find the zeros of the function f(x) = tan(x) - 2 Then there are Taylor Series, etc. Your best bet is just to use a calculator (online or mechanical), just as you would to fine log(12) or e^3.1 or any other ...

*September 19, 2016*

**Trigonometry**

you evidently need to review the definitions of the basic trig functions. In this case, tanθ = 75/100

*September 19, 2016*

**math**

well, just look. They added just one textbook, and the weight grew by 1 kg. Clearly the extra textbook weighed 1 kg. Or, algebraically, 3d+3t=9 3s+2t=8 subtract and you get rid of the d's, leaving 0d+1t = 9-8 t=1

*September 19, 2016*

**Maths**

3*39 = 3^2 * 13 now turn that into a list of all factors

*September 19, 2016*

**maths**

with a little expansion, you can arrive at sin(5x)+sin(7x) = 4sin(x) cos^2(x) (2cos(2x)-1) (2cos(2x)+1) now the roots are easy to find.

*September 19, 2016*

**mathematics help**

unusual to have complex coefficients, but x^2 = -16j = 16cis(3π/2) x = ±4 cis(3π/4) = ±4 (-1/√2 + 1/√2 j) = ±2√2 (-1+j)

*September 19, 2016*

**science**

the mass does not matter. a = (20m/s)/(5s) = (20/5) m/s^2

*September 19, 2016*

**mathematics need help**

since the slope is 3, start with x = t y = 3t since the y-intercept is -2, y = 3t-2

*September 19, 2016*

**calculus help me asap**

Here's what wolframalpha.com ends up with: http://www.wolframalpha.com/input/?i=derivative+y%5E6%3Dtanh%5E-1(tan%5E-4(4x%5E2%2By%5E2)%5E2)%5E9 That's as you typed it. I interpreted it as http://www.wolframalpha.com/input/?i=derivative+y%5E6%3Dtanh%5E-1(tan%5E-4((4x%5E2...

*September 19, 2016*

**calculus help me asap**

this is just stupid. y^6 = tanh^-1(u)^9 6y^5 y' = 9 tanh^-1(u)^8 * 1/(1-u^2) du/dx where u = tan^-4(v^2) and v = 4x^2+y^2 = cot^4(v^2) du/dx = 4 cot^3(v^2) (-csc^2(v^2)) (2v dv/dx) dv/dx = 8x + 2yy' mash all that together and solve for y' I see little to be gained ...

*September 19, 2016*

**Maths**

well, 40 = 5*8 55 = 5*11

*September 19, 2016*

**Maths**

not sure what the :||+|| means and it appears you have too many = signs but yes, 2*2 = 4

*September 19, 2016*

**math**

3d+2t = 8 3d+3t = 9 clearly, t=1

*September 19, 2016*

**Math 115**

for 100 < P, C(P) = 100 + 0.72(P-100) or C(P) = P - 0.28(P-100)

*September 19, 2016*

**Math 115**

for 30 < t <= 40, D(t) = D(30) = 2 for 40 < t <= 65 D(t) = 2 + (1/60)(t-40)

*September 19, 2016*

**math**

60/x = sin30°

*September 19, 2016*

**Math115**

t is in minutes, and D is in miles. Since the speed is given in mi/hr, you have to divide that by 60 to get mi/min

*September 19, 2016*

**Math115**

why all the words? Just say D(t). I'll do the first piece. See what you can do with the rest. Starting from t=0, having gone 0 miles so far, D(t) = 0 + 4/60 (t-0) for 0 <= t <= 30 = 1/15 t That may seem cumbersome, but therein lie hints for the other parts.

*September 19, 2016*

**Algebra**

since the slope m is constant, (13+5)/(3-r) = m You have not included the value of m, but once you divulge that secret, you can find r.

*September 18, 2016*

**math**

since the model is 1/16 as big, just divide all the dimensions by 16: boat: (17/16) ft car: (20/16) ft You might want to express those in inches

*September 18, 2016*

**Math**

x^2 - 2x it's as valid as any other expression.

*September 18, 2016*

**Physics**

v = 9.8t s = 100 - 4.9t^2

*September 18, 2016*

**College Algebra**

why the inconsistency? Either say 4 less than t less than or equal to 6 or, my favorite, 4 < t <= 6 For that piece, we have C(t) = 4 for 4 < t <= 6 see what you can do with the others.

*September 18, 2016*

**Math**

how come you can say + but cannot say - ???? 1/4 + 2/7 + 11/12 - 3/4 = 2/7 + 11/12 - 1/2 = 24/84 + 77/84 - 42/84 = ...

*September 18, 2016*

**Math**

(81+11 - 8*4)*1 = 60

*September 18, 2016*

**math**

355-2 < v < 355+2

*September 18, 2016*

**physics**

without relying on friction, I assume you mean that the cars scrape along the wall, since they cannot grip the road without friction.

*September 18, 2016*

**Math**

total = each * number

*September 18, 2016*

**physics**

just figure total load weight so that it equals the weight of the air displaced.

*September 18, 2016*

**math**

you need to distinguish between asking a question and giving instructions. Question: What is the total number of acres planted? Instructions: Compute the total number of acres planted. Now that the English lesson is done, on with the math ... Just add up the amounts. The LCD ...

*September 18, 2016*

**MathEmatics**

yes why not just write 1/20?

*September 18, 2016*

**Physics**

going across the puddle, s = 20t - 1/2 at^2 = 25 v = 20 - at = 5 solve for a and t.

*September 18, 2016*

**Math**

how many face cards are there? chance of getting 1: ? with one missing, chance of getting another: ? multiply the two.

*September 18, 2016*

**Calculus III**

For P:(x,y,z) distance from P to the x-axis: √(y^2+z^2) distance from P to the yz-plane: x So, √(y^2+z^2) = 4x y^2+z^2 = 16x^2 x^2/1 - y^2/16 - z^2/16 = 0 I'll get back to you on the rest.

*September 18, 2016*

**English**

only #1 is clear and concise. #5 is more explicit, but in a classroom setting, I think #1 implies #5. You certainly don't want to talk about the summary, rather than the passage.

*September 18, 2016*

**Math**

14*2/7-3+9 = 10

*September 18, 2016*

**Math**

it's even easier to see if you call them x-2, x, x+2 what's the sum?

*September 18, 2016*

**Math**

there are 5 choices, but only 1 is a success. So, that means there are 4 wrong choices. The odds are 4:1 against, or 1:4 in favor. The probability of a 5 is 1/5. odds are the ratio of success:failure

*September 18, 2016*

**Math**

3*4 = 12 3*5 = 15 so, ...

*September 18, 2016*

**math**

e^x: 2.718 7.389 20.08 54.598 148.413 403.428 so, it grows faster than e^x as x gets large maybe e^(kx^2) can be adjusted some. Since it is not at all obvious (to me), and since there are only 6 data points, it will be e possible to fit any suitable polynomial or exponential. ...

*September 18, 2016*

**Math 2**

Hmmm. √3 sinx = 2+cosx 3sin^2(x) = 4 + 4cosx + cos^2(x) 3 - 3cos^2x = 4 + 4cosx + cos^2(x) 4cos^2(x) + 4cosx + 1 = 0 (2cosx + 1)^2 = 0 cosx = -1/2 Looks like that is a good starting point. Check for extraneous solutions.

*September 18, 2016*

**math**

I'm sure you can find the area A of a right triangle. The volume of the prism is just V = A*length

*September 18, 2016*

**Math**

the area scales as the square of the ratio, so it will be 800 * (3400/5000)^2

*September 18, 2016*

**Math**

total points: 60*100 top 30: 30*80 Now see how many points you have to divide among the other 70 students.

*September 18, 2016*

**math**

576/9 = 64 So, there were 4*64 muffins 5*64 cookies

*September 18, 2016*

**math**

x + 38b = 2.13 x + (38-26)b = 0.96 now just solve for x.

*September 18, 2016*

**Algebra**

first, find t. I assume these are speed * time calculations. Once you have t, use either expression to find the distance.

*September 18, 2016*

**Maths**

9/30 = 30% which had marks. So, we assume that 60 = 30% of the total.

*September 18, 2016*

**Math**

online we use ^ for powers. So, a^2 + x^2 = 4^2 x^2 = 16-a^2

*September 18, 2016*

**Math**

(x+5)/x = 4/3

*September 18, 2016*