Monday

July 25, 2016
Total # Posts: 42,082

**Maths**

If the bottle holds b and a pen holds p, then we are told 2b/3 - 7p + 2p = x/4 5b/12 = 5p b = 12p
*July 16, 2016*

**maths - eh?**

fix your typos
*July 16, 2016*

**CHECK MY ALGEBRA 2**

Hmmm. I don't see any theoretical solution, but after 55 iterations g(x)=4, so that the next time g(x) = 4-2|2-4| = 4-2*2 = 0 g(0) = 4-2|2-0| = 4-2*2 = 0 and it stays zero Maybe roundoff error contributes to this result.
*July 16, 2016*

**Math**

well, the length of the base is 2 * 10 * sin15°
*July 16, 2016*

**Math**

95 = 5*19
*July 16, 2016*

**Math linear equations**

first step: expand to lose the parentheses: 10x-15-9x+21 = 5 Think you can take it from there?
*July 15, 2016*

**Calculus1**

Huh? How is this even possible? Anyway, just use the product rule to get a = 1/2 r^2 θ da/dt = 1/2 * 2rθ dr/dt + 1/2 r^2 dθ/dt So, now all you ave to do is find θ when a=20 and r=5 Then plug that in to solve for dθ/dt
*July 15, 2016*

**maths**

I'd just find the midpoint of AC or BD, since the diagonals bisect each other.
*July 15, 2016*

**Precalc**

google is your friend https://www.artofproblemsolving.com/wiki/index.php?title=2007_AMC_12B_Problems/Problem_19
*July 15, 2016*

**precalc**

In triangle ABC, the angles are A=45 C=60 so, B=75 These are inscribed angles, so if you draw radii from the center O to each vertex, you have AOB = 2*ACB = 120 BOC = 2*BAC = 90 AOC = 2*ABC = 150 Now you have three isosceles triangles. Each triangle with central angle θ ...
*July 15, 2016*

**calc**

scalar times vector = vector All the other operations produce vectors, so the result is a vector. vector dot vector produces a scalar, but that's not used here.
*July 15, 2016*

**Business Math**

so, do you have the formula? Can you plug in your numbers?
*July 15, 2016*

**MATH**

recall the distance formula: √(4^2 + 5^2)
*July 15, 2016*

**Math**

so, since x and y are integers, clearly x=y=0 is a solution If x>0, 2x-1 > x unless x=1, so x=y=1 is a solution For x>1, x/(2x-1) is a fraction. For x<0, x/(2x-1) is always a fraction, so (0,0) and (1,1) are the only integer solutions.
*July 15, 2016*

**Maths**

There are 7C5 ways to pick the consonants There are 5C3 ways to pick the vowels Each set of 8 letters can then be rearranged in 8! ways. This is assuming no duplicate letters.
*July 15, 2016*

**Maths**

well, there are 6 ways to answer 5 of the 1st 6 correctly (the same as the number of ways to get one of them wrong) That leaves 6 questions, of which 4 can be chosen in 6C4 = 15 ways. Each set of 4 can be answered in 2^4 ways.
*July 15, 2016*

**Maths**

no idea what the Cross Method is, but maybe you can fit these solutions into it. After giving away 1/4, there were 3/4 left, so x - x/4 - (1/3)(3x/4) = 120 x - x/4 - x/4 = 120 x/2 = 120 x = 240 Similarly, if Linda started out with $x, x - x/4 - x/3 - (1/5)(5x/12) = 18.50 x - x...
*July 15, 2016*

**Maths**

recall the sides ratios for a 30-60-90 right triangle: 1:√3:2
*July 15, 2016*

**Johnson**

distance of elevator from man: 22+2.0t distance of object: 6.5t + 4.9t^2 So, when are they equal?
*July 15, 2016*

**Math**

Looks like 11 girls in line
*July 15, 2016*

**Math**

The hexagon consists of six equilateral triangles, each with height (the apothem) 4√3 base 8 Now you can easily get the area. To get the base, review the properties of equilateral or 30-60-90 triangles.
*July 15, 2016*

**maths**

Draw a diagram. Review your basic trig functions. If the height of the pole is h, then h cot45° + h cot68° = 10
*July 15, 2016*

**Algebra 2**

if you mean linear, it has a term of the form ax where a is a constant, and it has no higher powers of x. More generally, it can be written in a variety of forms: ax+by+c=0 ax+by=c y=mx+b y-k = m(x-h) I'm sure your text covers it in some detail.
*July 15, 2016*

**Math**

as shown earlier, 3log_2(-x-6)
*July 14, 2016*

**MATH**

log_a(3) = log_b(27) log_a(3) = 3log_b(3) log_a(3)/log_b(3) = 3 log_b(a) = 3 b = a^3
*July 14, 2016*

**Math**

log_2(x) has asymptote at x=0, so log_2(x+6) has its asymptote at x=-6 But, its domain is x > -6. So, we want log_2(-x-6) at x = -8, we have log_2(8-6) = 1 So, we want y = 3log_2(-x-6)
*July 14, 2016*

**Math(help please)**

all we know is that 1/25 of the items are red pens. Assuming an integer number of items, that makes C the only reasonable choice.
*July 14, 2016*

**Math**

sorry - no pictures here. Surely you can draw a reasonable picture of lines a and b. Let a be the x-axis Then b is the line y=x (45°) Now, line c will be parallel to the y-axis. So, you now have a right triangle with two 45° angles.
*July 14, 2016*

**MATH**

or, to avoid introducing a new base, f^-1(x) = log1/3x = -log3x log and exponentiation are inverses, just like + and - * and / square root and square We just don't have any special symbols to denote the operation.
*July 14, 2016*

**mathematics**

These would be all the multiples of 24.
*July 14, 2016*

**Math**

u.v = 5*3*cosπ/3 = 15 * 1/2 = ?
*July 14, 2016*

**pre cal**

just plug in your numbers: cosθ = u•v ----------------------- |u| |u|
*July 14, 2016*

**math**

70^2 + 120^2 + 2*70*120 cosθ = 90^2 cosθ = -2/3 θ = 131.8° This makes sense, since if the two forces were separated by an acute angle, the resultant would be greater than either of them. Think of the parallelogram involved.
*July 14, 2016*

**Math**

not sure what that is, but it is the graph of log_3(x) reflected through the y-axis shifted right by 3 stretched vertically by a factor of 2 shifted down by 2 Note that log_3(-3x+9) = log_3(3) + log_3(3-x) = 1 + log_3(3-x) This cancels the scale factor on the x-axis by ...
*July 14, 2016*

**Chemistry**

well, 12g C + 32g O2 → 44g CO2 ?? If all 18g of C were used, there would be only 66g CO2. Am I missing something here?
*July 14, 2016*

**algebra**

it will take t hours, where 1.039^t = 2
*July 14, 2016*

**Math**

you want y(0) = 5, so log3(k^2)-1 = 5 log3(k^2) = 6 k^2 = 3^6 k = 27
*July 14, 2016*

**Science**

write the balanced equation convert grams to moles find the limiting reagent see how many moles of it will be used see how many moles of H2O will result convert back to grams
*July 14, 2016*

**Maths**

The factors of 6262 are 1x6262 2x3131 31x202 62x101 The first two are out, since there's no room for the blue border and red interior. So now, check the others and pick the one which allows for more red tiles. 29x200 60x99
*July 14, 2016*

**physics**

since the speed is uniform, its average is 30km/h
*July 14, 2016*

**maths**

rather than from 2:00 to 11:00, I read it as moving from, say 12:10 to 12:55, or 9/12 of an hour.
*July 14, 2016*

**math**

the number is between 3500 and 4500 So, now we start working with the info. The hundreds digit is even, so 363x 384x 400x 421x 442x If the digits add to 12, that means we can have only 3630 4008 4215 4422 So, what do you think?
*July 14, 2016*

**math**

as with all boxes, it is length * width * height = 21√5 * 12√3 * 25√3 = 18900√5
*July 14, 2016*

**Math**

That's what I get.
*July 14, 2016*

**Math**

that will be h(10)-h(9)
*July 14, 2016*

**algebra**

As we know, h(x) = a+bx-16x^2 a+b-16 = 148 4a+2b-64 = 272 solve that and you end up with h(x) = 4 + 160x - 16x^2 ...
*July 14, 2016*

**Math**

since 1/4 = 6/24, use that ratio for all the numbers. Then you have 1/6 : 1/8 : 1/4 1/6 - 1/8 = 1/24 Or, 4-3 = 1 Now scale that and you get 1/24
*July 13, 2016*

**algebra**

slope = distance/time
*July 13, 2016*

**Math (PLEASE HELP!)**

since cos(t) has a max at t=0, and we want the passenger to start at the bottom, a will be negative. r=13, so h(t) = -13cos(bt)+d h(0) = 1, so h(t) = -13cos(bt)+14 The period is 24, so h(t) = -13cos(π/12 t)+14
*July 13, 2016*

**maths**

Clearly you were having trouble, as you posted no work of your own.
*July 13, 2016*

**maths**

Clearly the floor is 0.1m thick. So, multiply the volume by the unit cost, and you get a cost of (7*3 + 6*2)(0.1)(65) = ?
*July 13, 2016*

**math**

since distance = speed * time 4(s-20) = 3(s+20) and we know what airspeed: it's its speed in the air. (note apostrophe)
*July 13, 2016*

**maths114**

The area of the minor segment is 1/2 r^2 (θ-sinθ) So, plug in your values and subtract that from the area of the circle, πr^2
*July 13, 2016*

**Math**

If they lost x games, then we have x + 3x+15 = 95
*July 13, 2016*

**maths 114**

area of circle minus area of minor segment.
*July 13, 2016*

**math**

(x-1)y" + 2y' = 0 If we expand about x=0, we assume y = ∑anx^n y' = ∑nanx^(n-1) y" = ∑n(n-1)nx^(n-2) Plug these into our DE and we have (x-1)∑n(n-1)nx^(n-2) + 2∑nanx^(n-1) = 0 ∑n(n-1)nx^(n-1) - ∑n(n-1)nx^(n-2) + 2&#...
*July 13, 2016*

**Math**

well, since 3 = 18/6, the cost is X/6
*July 13, 2016*

**math**

well 64πh = 384π
*July 13, 2016*

**maths**

6cis 5π/6 * 3cis 4π/5 = 6*3 cos(5π/6 + 4π/5) = 18 cis 49π/30
*July 13, 2016*

**analytic geometry**

since (8,0) divides the line into a proportion, (8-x)/(10-x) = (0-7)/(y-7) y = 14/(x-8) There are many possible lines. A few possibilities are x=9, y=14 x=10, y=7 x=15, y=2 x=22, y=1 x = -6, y = -1 x = 1, y = -2 x = 6, y = -7 x = 7, y = -14
*July 13, 2016*

**math**

t = 2-x, so y = 1+2(2-x) = 5-2x At t=0, we have (2,1)
*July 13, 2016*

**Math**

If x is the original number, x/24 = x-16 Comes out a fraction. If, on the other hand, you meant to say he got a quotient which was 16 less than the correct quotient, then we have x/24 = x/12 - 16 x = 384 I suspect you have garbled the question.
*July 13, 2016*

**Maths - duh**

Stupid me. I read the question as "two equal parts" and wondered what the fuss was about. Clearly the ratio would be 1:1 Nice catch, Reiny.
*July 13, 2016*

**Maths**

what do you mean by "their areas"?
*July 13, 2016*

**math**

it has to make up 130 miles in 3 hours. So, its speed is 65 + 130/3 mi/hr
*July 13, 2016*

**pre-calculus**

well, for 30° it is (1/2, √3/2) Now move that around 180°
*July 13, 2016*

**computer sc.**

no diagrams, but the steps are n=50 i=0 sum=0 get score i += 1 sum += score i<n? If so, repeat avg = sum/n
*July 13, 2016*

**Pre Calculus**

or, more directly, using deMoivre: 8cis10 * 5cis200 = 8*5 cis(10+200) ...
*July 13, 2016*

**math**

just plug in the numbers where F = 9/5 C + 32
*July 13, 2016*

**math**

speed = distance/time, so 1.4km/1.667hr = 0.84 km/hr or, using fractions, (7/5)km/(5/3)hr = 21/25 km/hr
*July 13, 2016*

**Algebra**

6/20 --------- = 2/5 3/4
*July 12, 2016*

**Math**

y = a(x+3)(x+1)(x-4) at x = -2, (x+3)(x+1)(x-4) = 18 so, y = 4/3 (x+3)(x+1)(x-4)
*July 12, 2016*

**Pre-Cal**

Draw your triangles in standard position. Then it is clear that sinx = -4/5 tanx = 4/3 cosy = -√77/9 tany = -2/√77 Now just plug the needed values into the identities you have
*July 12, 2016*

**Pre-Cal (Help Please!!!!)**

#1 cosθ (3tan^2θ - 1) = 0 so, cosθ = 0 or tanθ = ±1/√3 Those are standard familiar values, right? #2 tan3θ = -1 3θ = 3π/4 or 7π/4 + n*π/3
*July 12, 2016*

**Math**

Just factor as usual: 2x + 9√x - 5 = 0 (2√x-1)(√x+5) = 0 √x = 1/2 x = 1/5 √x = -5 no solution there
*July 12, 2016*

**Algebra**

just expand and equate coefficients 4x^2+20x+r = 4x^2+4sx+s^2 4s=20 s=5 r = s^2 = 25 r-s = 20
*July 12, 2016*

**Physics**

F = ma, so a = F/m = 18N/6kg = 3 m/s^2 v = at = 3*5 Now you try the other. Same ideas.
*July 12, 2016*

**maths studying for pre cal test**

draw angle A and side b. Now, if it were a right triangle, with b the hypotenuse, side a would be the altitude, of length 14 sin60° = 12.12 So, you see, a little side a of length 4 will not reach down the the base, AB. If C is the right angle, that means that tanA = 6/14, ...
*July 12, 2016*

**Studying for math test**

Read the question carefully. It said which of the following is not equivalent? Actually, both c & d are not
*July 12, 2016*

**Studying for math test**

take a look at the related questions below. In particular, http://www.jiskha.com/display.cgi?id=1468255540
*July 12, 2016*

**12th grade chemistry**

normalbold
*July 12, 2016*

**12th grade chemistry**

<pre> abc def ghi jkl </pre>
*July 12, 2016*

**12th grade chemistry**

<font size="4">size 4</font> <font size="2">size 2</font>
*July 12, 2016*

**12th grade chemistry**

abc<small>abc</small>
*July 12, 2016*

**science**

well, p = mv plug in your numbers and solve for v.
*July 12, 2016*

**chemistry**

note that each 2 moles of KOH produce 1 mole of Mg(OH)2. So, how many grams in 2 moles of magnesium hydroxide?
*July 12, 2016*

**MATHS**

42°
*July 12, 2016*

**MATHS**

3x+A=45 x = (45-A)/3 Is there something else you want to specify?
*July 12, 2016*

**Math**

or, differentiating y' directly, y" = 50y^3(-5xy^2+20xy+18)/(10xy+9)^3 y"(1,1) = 50(-5+20+18)/19^3 = 1650/6859 which agrees with Reiny's result above!!!
*July 12, 2016*

**physics**

How long does it take the bomb to fall 8000m? 4.9t^2 = 8000, so t=40 s In 40s, the bomb will travel 8000m. What a coinkidink! So, the angle is just 45°
*July 12, 2016*

**math**

just solve 3x + 1/2 x^2 = 8
*July 12, 2016*

**pre cal**

splashdown occurs when h=0 max height is at t = -b/2a = 115/9.8
*July 12, 2016*

**agebra**

well, if you know the mean and the std, µ-2σ <= x <= µ+2σ
*July 12, 2016*

**math**

dy/dx = xy dy = xy dx dy = 1*2 * 0.4 = 0.8
*July 12, 2016*

**pre cal**

recall that the vertex of a parabola is at t = -b/2a so evaluate h(t) there.
*July 12, 2016*

**maths**

Just change the numbers in Reiny's solution here: http://www.jiskha.com/display.cgi?id=1455402753
*July 12, 2016*

**pre cal**

well, the diagonal of the square is the diameter of the circle...
*July 12, 2016*

**pre cal**

The time it takes for the sound to come back is d/c The time it takes to fall a distance of d is found using h0 + v0 t - g/2 t^2 = d Solve that for t, and then you have t = 1/g (v0 + √(v0^2 - 2g(d-h0))) Now you know that 1/g (v0 + √(v0^2 - 2g(d-h0))) + d/c = t Now ...
*July 11, 2016*

**Algebra/Calculus**

note that (x+y)^2 = x^2+2xy+y^2 x^3 + y^3 = (x+y)(x^2-xy+y^2) Now just plug in what you know.
*July 11, 2016*

**algebra 2**

3x-15 = 0 when x=5 everything else is ok.
*July 11, 2016*