Thursday

September 29, 2016
Total # Posts: 44,235

**Math**

looks good to me

*September 20, 2016*

**Math**

well, how many ounces in 6 lbs? Divide that by 5oz/apple to get the no. of apples.

*September 20, 2016*

**6th Grade Maths**

45/(2 x 4.7 - 4.4) x 6 = 54

*September 20, 2016*

**Advanced Functions 12**

not sure what the secant lines mean. At x = 1/2, they all pass through 1/2 f(x) = (3 - 1/4)/2 = (1/2,11/8) That won't get anywhere near the tangent line, no matter what other point you choose. I suspect there is something left unsaid here.

*September 20, 2016*

**Math**

well, the list of running times is 5,7,8 can you not figure the range of such a list?

*September 20, 2016*

**calculus need help**

Really. Ha you know that the solution of y" + y = 0 is y = a sinx + b cosx Now use the method of variation of parameters: We now have y1 = sinx y2 = cosx The Wronskian of {sinx,cosx} is -1 u1 = ∫cosx tanx dx = ∫sinx = -cosx u2 = -∫sinx tanx dx = ∫...

*September 20, 2016*

**math**

cannot access files stored on your computer. duh.

*September 20, 2016*

**Math**

(1/3 ft)/ (1/6 yd) but, since 1 yd = 3 ft, you have = (1/3 ft) / (1/2 ft) = (1/3) / (1/2) = 2/3

*September 20, 2016*

**maths**

You have three unknowns, and only two equations. Here is what wolframalpha.com says: c+s+h = 100 5c + s/10 + 2h = 100 http://www.wolframalpha.com/input/?i=solve+c%2Bs%2Bh+%3D+100,+5c+%2B+s%2F10+%2B+2h+%3D+100 There is no unique solution, but if you play around, you can see ...

*September 20, 2016*

**algebra**

correct

*September 20, 2016*

**algebra**

what do you mean by "write a full" ? Note that as x grows by 1, y grows by 2. SO, start wity y = 2x Now adjust that so that the values agree with those in the table.

*September 20, 2016*

**Math**

5.25/.75 = ?

*September 20, 2016*

**Math**

Why have two variables? Each function has a flat fee and an hourly rate. The only variable is the time. You want the time to be such that the two cost are equal. Where did you get the 2? You're not multiplying by the number of service calls. Each service call has a flat ...

*September 20, 2016*

**Math**

well, st = u + v/2 now just one more step to go...

*September 20, 2016*

**math**

again? See your first post, or the related questions below

*September 20, 2016*

**Math**

if moving in the same direction as the bus, just add the speeds. If moving in the opposite direction, subtract her walking speed from the bus's speed.

*September 20, 2016*

**Math**

No. It grows 144/7 = 20.57 inches. Think about it. It takes 7 days to grow 6 inches. 24 is a little more than 3*7. So, it will grow a little more than 3*6 = 18 inches. You need to work on your reading, too...

*September 20, 2016*

**Math**

If it were 21 days, since 21 = 7*3, it would grow 6*3 = 18 inches. 24 is not quite that simple. It grows (24/7) * 6 = 144/7 inches why did you multiply 6 by 4? You cannot multiply days by inches. The units make no sense. Instead, you want to convert days to inches, using the ...

*September 20, 2016*

**math**

see earlier post

*September 20, 2016*

**Math**

draw the vectors. Since they are perpendicular, the resultant is just the hypotenuse of the triangle.

*September 20, 2016*

**Jewelry**

Seems like I read about this necklace in a mystery novel...

*September 20, 2016*

**math**

solve as you would an equation. The only thing to watch for is to change the direction of the inequality when multiplying by a negative quantity. 2(3x−6)>=5x-10 6x - 12 >= 5x-10 6x-5x >= -10+12 x >= 2 So, pick out all the values at least 2. To be sure, ...

*September 20, 2016*

**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*