Saturday

February 25, 2017
Total # Posts: 48,782

**physics**

general equation x = a sin(b(t-c))+d Since equilibrium is x=0, d=0 x = a sin(b(t-c)) the period is 9, so b = 2?/9 x = a sin(2?/9 (t-c)) If it travels .4 m in a cycle, the amplitude is 0.1, so x = 0.1 sin(2?/9 (t-c)) Now we have a problem. If x(0) = -0.1, that is its minimum ...

*February 13, 2017*

**Algebra**

.20x = 1

*February 13, 2017*

**math**

42 lbs

*February 13, 2017*

**099**

4x - 30 = -3x - 32 add 3x to both sides 7x - 30 = -32 add 30 to both sides 7x = -2 divide by 7 x = -2/7

*February 13, 2017*

**099 math**

1st step: lose the parentheses: 2(2x-7)-16=3(-x-7)-11 4x-14-16 = -3x-21-11 . . .

*February 13, 2017*

**Math**

angle C = 85° (180-52-43) Labeling the sides a,b,c opposite angles A,B,C, you want side b, since angle B is the smallest angle. b/sinB = c/sinC b/sin43° = 50/sin85° Now just solve for b

*February 13, 2017*

**science**

it takes (50-30)/10 = 2 seconds to reach the final velocity. s = 30t + 1/2 t^2 Now just plug in t=2.

*February 13, 2017*

**Calculus**

1. Just use the power rule recall that 1/x^2 = x^-2 2. product and chain rule: y = x^5 (1+x)^5 y' = 5x^4 (1+x)^5 + x^5 * 5(1+x)^4 = 5x^4(1+x)^4 (1+2x) 3. quotient rule. Assuming the usual carelessness with parentheses, y = (4-x^2)/(2x+3) y' = [(-2x)(2x+3) - (4-x^2)(2...

*February 13, 2017*

**Algebra**

the slope-intercept rule is called that for a reason... Q2. y=kx, so y/x=k, a constant. You want y such that y/10 = 24/8

*February 13, 2017*

**Algebra**

huh?? !! 13/16 = 0.8125 h(13/16) = -16(13/16)^2 + 26(13/16) + 5 = 249/16 = 15.5625 or, h(.8125) = -16*.8125^2 + 26*.8125 + 5 = -10.5625+21.125+5 = 15.5625 Too bad you couldn't be bothered to show your work ...

*February 13, 2017*

**Algebra**

don't forget your Algebra I. h(t) is just a quadratic, and the vertex (maximum height) is at t = -b/2a = 26/32 = 13/16 Now use that to find h(13/16)

*February 13, 2017*

**Maths**

Sn = n/2 (A1+An) = 8/2 (6+46)

*February 13, 2017*

**Trigonometry**

4rpm = 16 in/min, so 1 rev = 4in 2?r = 4, so r = 2/? for the 8" wheel, the ratio of radii is 8/(2/?) = 4? So, if its radius is 4? as big, its speed is 1/(4?) as fast, or 16/(4?) = 4/? in/min It makes 1/(4?) * 4 = 1/? rpm Your unknown radius is ok, but I don't see how ...

*February 13, 2017*

**Calculus for Business Administration and social s**

?(432x^12) = ?(8*27*2 x^12) = 6x^4 ?2

*February 13, 2017*

**Maths**

Let the length AM=1. Let C be the midpoint of AM. Draw the line CO. It has radius 1/2 + r. Draw the line MO. It has length 1-r. So, in the right triangle CMO, 1/2^2 + (1-r)^2 = (1/2 + r)^2

*February 13, 2017*

**math**

you know that the length is between 19.5 and 20.5 meters the width is between 2.5 and 3.5 meters So, use the largest and smallest values to get the range of perimeters.

*February 13, 2017*

**Math 115**

45-4.5t

*February 13, 2017*

**Math 115**

I'll do one: C(t) = 45 - (45-27)/4 * 4 - (27-18)/2 * (t-6) = 27 - 9/2 (t-6) = 54 - 9/2 t if 6 < t <= 8 This should give a clue to the other parts...

*February 13, 2017*

**math**

average value is integral divided by the interval width.

*February 13, 2017*

**math**

I'm guessing you meant ?[4,7] (1+x^2) sinx dx or something. Try reposting with better notation. You can also use my notation above at wolframalpha.com to evaluate integrals.

*February 13, 2017*

**math**

not quite clear on your notation, but the distance is the integral of the velocity over the interval.

*February 13, 2017*

**Physics**

recall that KE = 1/2 mv^2 PE = mgh Now just plug in your numbers.

*February 12, 2017*

**Statistics**

visit this site for Z table stuff: http://davidmlane.com/hyperstat/z_table.html

*February 12, 2017*

**Trigonometry**

Good work, but I interpret the wheel size as the diameter. If so, same steps apply, just adjusted for the smaller radius.

*February 12, 2017*

**Stats**

you can play around with Z table stuff here: http://davidmlane.com/hyperstat/z_table.html For this problem, you find that 99.7% of the area lies less than 2.748 ? above the mean.

*February 12, 2017*

**Algebra**

12r+11s = 228 6r+5s = 108 ...

*February 12, 2017*

**Math**

I don't know what you mean by it "didn't work." It just shows that the expression is never positive. (x-2)^2 is a square, so it is always positive So, -(x-2)^2 is never positive. Trying to plug a formula into a request for a proof will never work. The logic ...

*February 12, 2017*

**Math**

= -(x^2-4x+4) = -(x-2)^2

*February 12, 2017*

**Algebra**

x+y = 900 .05x + .08y = 64.50

*February 12, 2017*

**Algebra**

12a+2c = 122 7a+8c = 160 ...

*February 12, 2017*

**science**

Ca comprises 2/3 of the 1.28g CaCO3, or 0.853g So, assuming that all of the calcium is contained in the CaCO3, the 0.853g is 31.37% of the 2.72g pill

*February 12, 2017*

**college math**

The maximum area occurs when the fencing is divided equally among lengths and widths. For all 4 sides fenced, that is a square. In this case, with the length parallel to the wall, we have length=500/2 = 250 and width = 500/2/2 = 125 so the area is 250*125 = 31,250 This is ...

*February 12, 2017*

**math**

try typing the equations yourself; copy/paste does not do well here. You can copy and paste the ? symbol as you go.

*February 12, 2017*

**math**

.13x + .09(x+700) = 239 x = 800 as above.

*February 12, 2017*

**Geometry**

Draw diagonals AC and DF. The hexagon is now divided into a parallelogram (rectangle?) and two congruent triangles. AC and DF can be found using the law of cosines, since all the interior angles are 120 degrees.

*February 12, 2017*

**math**

what you mean is 2 <= x <= 5 This is just a parabola, with vertex at (2,-1). So, clearly, f(2) = -1 is the minimum value. The axis of symmetry is at x = 2, so f(5) will be the max on the interval [2,5], since it is away from the axis.

*February 12, 2017*

**Algebra**

So, why not use a 1? |3y+4|-1 = 0 |3y+4| = 1 3y+4 = 1 3y = -3 y = -1 3y+4 = -1 3y = -5 y = -5/3

*February 12, 2017*

**algorithm**

for i=1 to 5 prompt for marks read marks[i] next i

*February 12, 2017*

**number base help plz**

1234 = 4^2 + 2*4 + 3 = 2*8 + 8 + 3 = 338

*February 12, 2017*

**College calculus**

x = u/(1 + u^3) y = u^2/(1 + u^3) dy/dx = dy/du / dx/du dy/du = u(2-u^3)/(1+u^3)^2 dx/du = (1-2u^3)/(1+u^3)^2 dy/dx = u(2-u^3)/(1-2u^3)

*February 12, 2017*

**Mathematics of finance 1**

see related questions below

*February 12, 2017*

**maths**

bricks: 180*6*50 * 8 = ? tank: Assuming a square base, v = 150*150*40/1000 L

*February 12, 2017*

**math**

the principal (not principle) can be found by solving P*1.04^2 - P = 1632 P(1.04^2-1) = 1632 ...

*February 12, 2017*

**math**

If x is at 3%, then the rest (12000-x) is at 5%. So, add up the interest: .03x + .05(12000-x) = 460

*February 12, 2017*

**math**

If he traveled x miles by bus, then he went 1900-x by plane. Since time = distance/speed, x/60 + (1900-x)/700 = 5

*February 12, 2017*

**basic calculus**

w = width 54/w = height The page area is thus a = (w+1)(54/w + 2) Assuming you want minimum page area, da/dw = 0 at w = 3?3

*February 11, 2017*

**Math**

The amount of bacteria after n seconds is A = Q*3^(n/15)

*February 11, 2017*

***physics***

1W = 1J/s = 1N-m/s so, 3500 kg * 9.8N/kg * 9.50m /(9000N-m/s) = 36.2 s

*February 11, 2017*

**Physics**

PV=kT, so PV/T is constant You want T such that 2*25/(T+273) = 1*20/(120+273)

*February 11, 2017*

**Math**

Try using the minus (-) sign for subtraction, not the underscore (_)! Anyway, you got them almost all wrong: -4+6+9y = 2+9y (since 6-4=2) 20a+7+3 = 20a+10 -5k+9-2+9k = 4k+7 OK 17+2.9h+3 = 20+2.9h -4(3+d)+7d-d = -12-4d+7d-d = -12+2d 8+5(j-5)+3j-1 = 8+5j-25+3j-1 = 8j-18 9(b-3)+4...

*February 11, 2017*

**math**

1.065x = 160000 x = 150234.74

*February 11, 2017*

**math**

125-(7+9-5) = ?

*February 11, 2017*

**math**

I don't know, but since y = x+2, x-2 = (5/6)x+1 Now solve for x, and then y=x+2

*February 11, 2017*

**MATH TEST(tipps)**

As longs as you're studying, work on your English: I have a math test in a week; plz give me some tips so I can pass it

*February 11, 2017*

**maths**

well, if u = x-y v(u) = u/3

*February 11, 2017*

**maths**

A*(x,y)T = (4,4)T (x,y)T = A-1(4,4)T

*February 11, 2017*

**Algebra 2**

Not sure I get this step, since ^ is right-associative: 3^(1/2)^x = a^(1/6) 3^3^x = a As written, that means 3^(3^x) I was thinking (3^(1/2))^x = a^(1/6) 3^(x/2) = a^(1/6) 3^(3x) = a 3^3 = a^(1/x) = a^b 1/x = b x = 1/b

*February 11, 2017*

**Math**

(203/2.2)/40 * 10 = 23.07 mg

*February 11, 2017*

**Calculus 2**

actually, it appears I was right after all...

*February 10, 2017*

**Calculus 2**

I may have misspoken. Take a look here for a discussion of the topic. faculty.atu.edu/mfinan/2243/business65.pdf

*February 10, 2017*

**Calculus 2**

Money at 2% grows like e^0.02t The amount deposited at time t gets to grow for (9-t) years. Seems to me like the account balance after 9 years is thus ?[0,9] R(t) * e^(.02(9-t)) dt

*February 10, 2017*

**math**

(1 1/2)(1/2) = 3/4 So, the new dimensions are 3/4 the original ones. You can do the math now...

*February 10, 2017*

**Algebra**

see related questions below.

*February 10, 2017*

**Algebra**

Not sure just what you're after. If the sums in the ratio 3:1 are just the first five terms, then a^2(1-r^10)/(1-r^2) ------------------------- = 3 a(1-r^5)/(1-r) ar = 4/3 a = 4/(3r), so plug that in, and (4/(3r))^2(1-r^10)/(1-r^2) ------------------------- = 3 4/(3r)(1-r^...

*February 10, 2017*

**Math**

cutting out the fat (!) (16^2/6^2) * 630 / 8 = 560

*February 10, 2017*

**Math**

3/5 x + 100 = 2/3 x x is in mL Now just solve for x. And that's liters, not literature!

*February 10, 2017*

**Mathematics**

the volume of the orange is ? * 12^2 * 6.75 = 972? cm^3 Now use what you know about the volume of a sphere to get the radius of the orange, and thus its surface area.

*February 10, 2017*

**Math College freshman**

(-100-20)/(40-20) = -6 so, the slope is -6, and we start with h = -6x But -6(20) = -120, and h(20) = 20. So h(x) = -6x + 140 You can check to make sure this fits the other points as well.

*February 10, 2017*

**College Algebra**

.15*5 = 0.75 So, T = .15p+0

*February 10, 2017*

**Math 115**

Clearly, W = 5x+5 The answer key must have an error.

*February 10, 2017*

**Math**

correct on both

*February 9, 2017*

**Cmax**

Any decent calculator has a button for ex somewhere. Probably an alternate function for ln.

*February 9, 2017*

**Science**

the filament has electrical resistance. When electricity passes through it, it generates heat -- so much heat that the wire glows.

*February 9, 2017*

**math**

Nope. The rate of growth is the slope of the line. Study (D) to see why it is the choice.

*February 9, 2017*

**math**

(b^2)^0 = 1 = b^8 So, b = 1 or -1 Just use the rules of exponents as usual. Negative values are still just numbers! p(p^-7q^3)^-2q^-3 = p * (p^-7 q^3)^-2 * q^-3 = p * p^14 q^-6 * q^-3 = p^15 q^-9

*February 9, 2017*

**Math**

.49p = 72.89

*February 9, 2017*

**math**

try writing them as 26x - 12y = 4 9x - 12y = -30 Now just subtract the equations and the y's will vanish.

*February 9, 2017*

**English**

Bob, I am a 70-year-old grandfather trying to help his grandson. Yes, I have read the book. After going and checking the difference between limited and omniscient I would say that the right answer should be 1st person omniscient.

*February 9, 2017*

**English**

The great gatsby is written in which point of view. 1st person limited 1st person omniscient 3rd person limited My answer is c

*February 9, 2017*

**Calculus prince@18**

h(x) = ?[2,x^2] arctan(t) dt from the 2nd Fundamental Theorem of calculus (and the chain rule), h'(x) = arctan(x^2) * 2x if F(t) = ?arctan(t), then h(x) = F(x^2) - F(2) now the chain rule gives the result, and d/dx F(2) = 0 If we had had h(x) = ?[lnx,x^2] arctan(t) dt then...

*February 9, 2017*

**math**

1 3/2 is bogus. Mixed numbers do not generally have a fractional part greater than 1. Anyway, 3^2 = 9 1 3/2 = 5/2 = 2.5 and now it should be clear. Do the others by putting them all over a common denominator (8), and then just sort the numerators.

*February 9, 2017*

**PHYSICS**

the fine article in wikipedia on "trajectory" explains this and more. The formula for the range is R = v^2/g sin(2?)

*February 9, 2017*

**Math**

the slope is -3/5 So, now you have a point and a slope. The line is y-4 = -3/5 (x+6) They don't call it the "point-slope" form for nothing!

*February 9, 2017*

**Algebra II**

neither one is. (a+b)^2 = a^2 + 2ab + b^2 neither one of these has a middle term. No idea what the "original monomial" could be. x? 4? 2?

*February 9, 2017*

**math**

why ever would you subtract radius from height? The volume of towels is the volume of the whole package, minus the volume of the inner cylinder. Recall that the volume of a cylinder is v = ?r^2 h. So, the volume of the towels is ?*12^2*18 - ?*5^2*18 = 2142? cm^3

*February 9, 2017*

**Math/Chemistry**

Have you forgotten your Algebra I? Ao/A = kt Ao = Akt

*February 9, 2017*

**Geometric problem solving**

first off, the circumference is measured in meters, not m^2. If C = 2?^2, then 2?r = 2?^2 r = ? So, A = ?r^2 = ?^3 m^2 If you meant to find the circumference when the area is 2?^2 m^2, ?r^2 = 2?^2 r^2 = 2? r = ?2? C = 2?r = 2??2? = (2?)^(3/2) Actually, I think you just messed ...

*February 9, 2017*

**math**

convert all to have the same power of 10, then it will be clear. For example, 2.3 * 10^5 = 230 * 10^3

*February 9, 2017*

**Math**

1/6 * 1/6 * 1/6

*February 9, 2017*

**Precalculus**

<k,2>•<3,5> = 0 3k+10 = 0 k = -10/3 gotta watch those ± signs!

*February 9, 2017*

**Math**

13/14 = 0.92857 = 92.857% The remainder from 13/14 is 13! Try some other number, say 72/13 = 5 7/13 = 5 R 7 The remainder is always less than the divisor, so 13/14 = 0 13/14 = 0 R 13

*February 8, 2017*

**Finance**

Which type of debt is the least attractive for a consumer? Unsecured debt Secured debt Mortgage debt Lease debt My answer is unsecured debt

*February 8, 2017*

**Math**

2(4+6) * $4.84

*February 8, 2017*

**Math**

no, that would make the answer 8m=102 ...

*February 8, 2017*

**math**

Note that you have two right triangles, with a common angle. So, they are similar, with all angles equal.

*February 8, 2017*

**Algebra**

well the function f is usually written in the form f(x) = 2x-2 so D looks like the choice intended. But saying Volume(radius) = 67 is a bit strange, since it implies that no matter which value "radius" has, the Volume remains constant at 67. If the value of Volume is...

*February 8, 2017*

**math**

I see that this time you omitted the instructions to make a Venn diagram. Did you do that, or are you just waiting for the answers? It appears that you must have meant 6 study only biology since you already said that 60 study biology. I think there is still something missing ...

*February 8, 2017*

**Math**

You might have check my solution given earlier before reposting the problem: http://www.jiskha.com/display.cgi?id=1486538658

*February 8, 2017*

**examples of pop singers**

Do you have some inappropriate ones in mind???

*February 8, 2017*

**math**

There are lots of online calculators, such as https://www.emathhelp.net/calculators/calculus-2/simpsons-rule-calculator/?f=1%2F%28x%5E5%2B7%29%5E%281%2F3%29&a=0&b=1&n=4&steps=on

*February 8, 2017*