Tuesday

February 9, 2016
Total # Posts: 37,527

**statistics help please**

͡° ͜ʖ ͡°
*December 12, 2015*

**Algebra**

all polynomials are defined for every real number. So, the domain is all reals. Since a sloping line extends forever in both directions, what's your best guess as to the range? Surely you can fill in the table. Just multiply x by 6, right?
*December 12, 2015*

**Algebra**

x-intercept is where y=0 y-intercept is where x=0 so, just plug in 0 for y or x and find the two intercepts. Then just connect them with a line. Done.
*December 12, 2015*

**calculus**

just divide each term by x^2 and use the normal power rule: ∫x^n dx = 1/(n+1) x^(n+1)
*December 11, 2015*

**math**

This can be easily confirmed by noting that the equation is an ellipse: (x-1)^2/16 + (y+2)^2/4 = 1 The major axis is on the line y = -2, so that's where the tangents are vertical.
*December 11, 2015*

**Ap physics 1**

If we set the center of mass at 0, then we have 3.12*10^5 * 2.46*10^8 = m*d where m is earth's mass and d is the distance to the center of the planet.
*December 11, 2015*

**Physics grade 11-**

72 km/hr = 20 m/s So, the deceleration is (20m/s)/(.1s) = 200m/s^2 Now the force F=ma, so ...
*December 11, 2015*

**Calulus**

The FTC says that the value is F(6)-F(1) where dF/dx = 4e^x-3 F(x) = 4e^x - 3x + c F(6) = 4e^6 - 18 + c F(1) = 4e^1 - 3 + c So, ∫[1,6]4e^x-3 dx = 4e^6-4e-15
*December 11, 2015*

**Calulus**

y = 2x^3-3x^2+9x+5 y' = 6x^2-6x+9 y" = 12x-6 Now, just apply the basic rules extrema at y'=0 and y"≠0 y increasing where y' > 0 y concave up where y" > 0 inflection points at y"=0 Note: There may not be any extrema, and so on. ...
*December 11, 2015*

**Algebra 1**

try using the two-point form of the line. Your two points are (2,-17) and (8,-47)
*December 11, 2015*

**Algebra 1**

pick the one best suited to the problem. You know that you have a rate 0\of .50 for every mile. So, if x is the number of miles, you know you will have something like y = .5x But you have a flat fee of 4.25, regardless of the miles, which is tacked on as soon as the meter ...
*December 11, 2015*

**Calulus**

base side x height y 2x^2+4xy = 300 ==> y = (300-2x^2)/(4x) v = x^2y = x^2(300-2x^2)/(4x) = 75x - x^3/2 dv/dx = 75 - 3x^2 dv/dx=0 at x=5 So, the shed is 5x5x12.5, with v=312.5 ft^3
*December 11, 2015*

**Math**

since distance = speed * time, if the current is c and her speed is s, 35(s-c) = 1.75 15(s+c) = 1.75 Now just solve for c.
*December 11, 2015*

**Calculus**

cube side = x, so the area a = 6x^2 da/dt = 12s dx/dt Now just plug in your numbers.
*December 11, 2015*

**Pre Algebra**

Judging by the choices, I guess the burn time is in hours. So, you want the height h = 3*24/15
*December 11, 2015*

**Pre Algebra**

I suspect a typo: 80 should be 90. If so, then clearly, the burn time is just 15 times the height. You don't say whether the time is in hours or minutes. I suspect minutes, but that will require quite a tall candle, if you figure out how many minutes there are in 3 days.
*December 11, 2015*

**Math**

nope. Just the definition of the sine: h/14 = sin 70° For the law of cosines, you need two sides and their included angle.
*December 11, 2015*

**Math**

original b = h+3 (1/2)(b+3)(h+3) = (1/2)(h+6)(h+3) = 14 Now just solve for h, and then get b.
*December 11, 2015*

**hbi pact for adults**

well 50 lbs is 50 times a much as 1 lb, so expect 50 times as many nails.
*December 11, 2015*

**math**

that would be 3000/200000 = 3/200 express that as a percent.
*December 11, 2015*

**Math**

Let's scale down the figure by a factor of 25, so it is similar to a triangle with sides 4,10,11 you can use Heron's formula. sqrt(12.5(12.5-4)(12.5-10)(12.5-11)) ≈ 20 or, you can note that 4^2 = 10^2+11^2-2*10*11*cos(x) cos(x) = (100+121-16)/220 = 41/44 the area...
*December 11, 2015*

**Chakote school solapur**

just use the formula: 1/R = 1/10 + 1/20 + 1/60 The voltage does not matter. The formula works because each resistor allows a current to pass, and the currents add up to the total. Since E=IR, I=E/R, and you have a total current of 12/10 + 12/20 + 12/60 That current is the ...
*December 11, 2015*

**maths (trigonometry)**

Notice how Damon cleverly descried a poorly constructed problem, and took a shortcut!
*December 11, 2015*

**Math**

Must be some special form. I tried an online integrator, and got (1/2)^(y+1) Γ(y+1)/y! But since Γ(y+1) = y!, that gives your answer. I'd suggest looking into integral forms involving the gamma function.
*December 10, 2015*

**Algebra**

you have the formula. Just plug in t=6 To find how long it takes to get to a million, 2105.22e^0.03t = 1000000 e^.03t = 475 .03t = ln 475 = 6.1633 t = 205.44 years Looks like 3% isn't gonna cut it, especially if you include inflation.
*December 10, 2015*

**Math factoring**

15x^2-35x+10 5(3x^2-7x+2) 5(3x-1)(x-2)
*December 10, 2015*

**Math question word**

x = desktop cost y = laptop cost x = y+350 .07x + .095y = 305 Now just solve for x and y
*December 10, 2015*

**Finite Math**

C(30,3) = 4060 any number means some subset of the power set of 30 elements. That is 2^30 = 1,073,741,824
*December 10, 2015*

**Math**

oh, ok total fruits: 12+4+8=24 so, now what do you think?
*December 10, 2015*

**Math**

'Twas brillig, and the slithey toves ...
*December 10, 2015*

**compare and order fraction**

or, if you use a common denominator -- in this case, 60. For example, 4/6 = 40/60 ...
*December 10, 2015*

**MATH**

Aside from the copy/paste of the inequality symbols, ok. Special symbols in various fonts get garbled at times. 22 <= 6x-2 <= 4x+16 24 <= 6x <= 4x+18 Now things start to get messy. You can't just subtract 4x from part of the setup; all or nothing. So, I'd ...
*December 10, 2015*

**math**

since 3/4 = 30/40, what do you think?
*December 10, 2015*

**MATH**

you can do both at once 3 < 5x-27 < 53 30 < 5x < 80 6 < x < 16
*December 10, 2015*

**@Damon - Nice Catch**

duh -- read twice, write once.
*December 10, 2015*

**Algebra 2**

Oops. That is just the integer lengths. I'm sure you can set down the two inequalities restricting x and y.
*December 10, 2015*

**Algebra 2**

7 <= x+y <= 22 So, just start listing x y 1 6..21 2 5..20 . . . 6 1..16
*December 10, 2015*

**math**

L=56+3D
*December 10, 2015*

**math**

3 months is 1/4 year, so discount by 2%
*December 10, 2015*

**Maths**

n(AuBuC)=12 n(AuB)=8, so n(C)=4 n(A'uB'nC)=n((AuB)'nC) That help?
*December 10, 2015*

**Math**

well, just plug and chug. f(x+h)-f(x) = 1/(x+h-1) - 1/(x-1) = ((x-1)-(x+h-1))/((x-1)(x+h-1)) = (x-1-x-h+1)/((x-1)(x+h-1)) = -h/((x-1)(x+h-1)) Now, divide that by h, and you have -1/((x-1)(x+h-1)) Now you can take the limit as h->0, and you end up with -1/(x-1)^2 at x=2, ...
*December 10, 2015*

**Pre-calculus**

This is just Algebra I. If there are a grams of A b grams of B .14a + .29b = 34.53 130a + 90b = 25430 Now just find a and b.
*December 10, 2015*

**Algebra**

they are the same, since multiplication is commutative.
*December 10, 2015*

**maths**

1/15th failed, so 14/15 passed
*December 10, 2015*

**Algebra discount price**

p-75 is ok But, a 55% discount means you only pay 45%, or p*.45 For C, just set them equal, as asked: p-75 = .45p .55p = 75 p = $136.36
*December 10, 2015*

**algebra**

OK. Y=28-6x. But, y>x, since it is the middle So, we have 28-6x > x 28 > 7x x < 4 So, we have several choices 3,10,18 2,16,13 1,22,8 ... But y is the middle, so only 3,10,18 works.
*December 9, 2015*

**geometry**

Note that the triangle described is a right triangle. The orthocenter is at the right angle, since the triangle can be inscribed in a circle, with the hypotenuse as the diameter.
*December 9, 2015*

**similarfigures**

it's called a proportion
*December 9, 2015*

**analtyic geometry**

so, add up the sides to make 260. That will give you x, and thus the dimensions of the yard.
*December 9, 2015*

**Math cosine law**

Did you draw your triangle? Did you review the law of cosines? x^2 = 185^2 + 325^2 - 2*185*325*cos18°
*December 9, 2015*

**Math**

the Greek letter is pi, NOT pie!! just use your addition formulas. sin(x-y) = sinx*cosy - cosx*siny Draw your triangles for x and y. sinx = √3/2 means cosx = 1/2 cosy = 12/13 means siny = 5/13 Now just plug in the numbers.
*December 9, 2015*

**Calculus**

all polynomials are continuous over their entire domain
*December 9, 2015*

**Maths**

well, you can see from the 2nd equation that 3y=7x-3. So, 6y=14x-6 Plug that into the 1st equation to find x, and then you can get y. Or, equivalently, multiply the 2nd by two and then you have 4x+6y = 21 14x-6y = 6 Now just add the two equations and y vanishes, leaving 18x=27...
*December 9, 2015*

**Math**

all polynomials are continuous over their entire domain
*December 9, 2015*

**Maths**

2x^2+8x-10 2(x^2+4x-5) 2(x+5)(x-1)
*December 9, 2015*

**Pre- Algebra**

the smallest set is the natural numbers: 1,2,3,... Next is whole numbers: 0,1,2,3,4... Next is integers: ...-2,-1,0,1,2,... Next is rational: these are all the fractions 1/2, 3/7, and so on Next is irrational: everything else Real numbers include all of the above Finally there...
*December 9, 2015*

**probability**

your first answer is the probability of drawing RRB in that order. But, if all you want is two reds and a blue, you need to multiply that by 3!/1!2!=3 because there are that many indistinguishable ways to reorder the balls. In other words, you have RRB, RBR, BRR They are all ...
*December 9, 2015*

**Math**

The angle does not really matter. Using similar triangles, h/20 = 30/52
*December 9, 2015*

**math**

9x10^8 / 3x10^7 = 9/3 x 10^1 = 30
*December 9, 2015*

**math**

#1 (a) and (b) Now, what are your thoughts on the others? I see no diagrams for 2,3,4
*December 9, 2015*

**Math**

What is the slope of your given line? Parallel lines all have the same slope.
*December 9, 2015*

**Math**

1/12 * 1/12 Given a drawn number, there is a 1/12 chance that it will be drawn next time.
*December 9, 2015*

**calculus**

or, you can integrate over dy, and avoid the split: In this case, the two lower bounding curves are x = y^2/4 x = 3-y ∫[2,4] y^2/4 -(3-y) dy = 14/3 Checking with Damon's method gives ∫[-1,1] 4-(3-x) dx + ∫[1,4] 4-2√x dx = 2 + 8/3 = 14/3 So, each ...
*December 9, 2015*

**algebra**

y = (6/3)x
*December 9, 2015*

**Geometry**

Complete the 2 column proof. Given m<rst = 5x and m<uvw = 7x <rstand <uvw are supplementary. Prove x=15 m<rst=5x and m<uvw=7x <rst and <uvw are supplementary given m<rst + <uvw = 180 definition of supplementary angles 5x+7x = 180 ? 12x=180 ? x=15 ?
*December 9, 2015*

**Math**

expand parentheses to get 36w+24+17+9w collect like terms to get 45w+41
*December 8, 2015*

**Algebra**

25*35 - (25-4)(35-4) =
*December 8, 2015*

**Physics**

clearly the angle is x (from directly ahead), where sin(x) = 25/31 If it takes t hours, then 0.3^2 + (25t)^2 = (31t)^2
*December 8, 2015*

**alegbra 2**

(7y+6)/(20x^2+20) = (21y+18)/(60x^2+60) just multiply top and bottom by 3
*December 8, 2015*

**Math**

what is 1/2 divided by 3?
*December 8, 2015*

**math**

c = 40.00 + .05m
*December 8, 2015*

**Geometry**

correct, if somewhat murky.
*December 8, 2015*

**Grover Cleveland high school**

study the equation of motion. If he indeed fell, starting at 10 m/s downward, then his height after t seconds was h(t) = 400 - 10t - 5t^2 But I doubt he pushed off with such a downward speed. Maybe you can modify h(t) to reflect the actual scenario.
*December 8, 2015*

**precalc**

I'll do a freebie for you. Maybe you can attempt the rest and show your work. The major semi-axis half the distance between the major vertices. Similarly for minor. #1: maj semi = 3 min semi = 2 x^2/4 + y^2/9 = 1 #3 is similar, but the center has been translated. Recall ...
*December 8, 2015*

**Math**

#1. Each nested side is 1/√2 as long as the previous side. Use that to find the length of the nth nested side. #2. Since the last digit is 8, there are 80 of them: 18,28,...808 Now you know the sum of the numbers from 1 to 80 is 80*81/2. So, you have 10 times that sum, ...
*December 8, 2015*

**Math**

I'll get you started with A. Its cost for n years is A(n) = 12500 + 300n + 3(36000/25)n do the same with B, changing the numbers as needed. Then you can make the table and compare costs for 2 years.
*December 8, 2015*

**Math**

right on.
*December 8, 2015*

**Math**

correct.
*December 8, 2015*

**Mulitvariable Calculus**

any text on vector analysis or differential geometry will discuss this topic. And google is your friend.
*December 8, 2015*

**math**

√x+y=11 x+√y=7 can't you think of some nice simple numbers that fit? The only perfect squares less than 11 are 4 and 9.
*December 8, 2015*

**math**

If those are supposed to be exponents, try 110(0.70^x) and so on The base of the exponent is the rate of change. So, 1.2^x indicates a 20% growth rate. Now it should be simple to sort by rate of growth (as a percent, not an absolute $$ amount)
*December 8, 2015*

**math**

No, it's B! Why not show your work, so we can see what's going on? How did you evaluate .01 * 2^17?
*December 8, 2015*

**math**

Nope. You want f(17)-f(10) --------------- 17-10
*December 8, 2015*

**algebra 2 trig**

One way to do this is to set up coordinates. Let A = (0,0) B = (-9,0) When A has sailed 5 miles, it lies on the circle x^2+y^2 = 25 The line through B with slope 0.4877 is y = .4877(x+9) This line intersects the circle at two places: (-4.5,2.2) and (1.0,4.9) So, you gotta be ...
*December 8, 2015*

**math**

cost(1+.20) = 40
*December 8, 2015*

**Algebra 1**

If the walkway has outside length of x, the inside length (the side of the garden) is x-8 SO, the garden has area (x-8)^2
*December 8, 2015*

**Math**

The ratio of ages of P and Q in 1996 was 2:3 and in 2001 it was7:10 What will be the ratio in 2011? in 1996: P/Q=2/3, so Q=3P/2 in 2001: (P+5)/(Q+5)=7/10 (P+5)/(3P/2+5)=7/10 P=30 so, Q=45 In 2011, (30+15)/(45+15)=3/4
*December 8, 2015*

**11U Functions Identity**

-sinx - cosx*cotx -sinx - cos^2x/sinx (-sin^2x - cos^2x)/sinx -1/sinx -cscx
*December 8, 2015*

**maths - incomplete**

how far is she from the building? It appears to have been omitted.
*December 8, 2015*

**Math**

p(~rain) = 1-p(rain)
*December 8, 2015*

**Trigonometry**

where sinA = 0, cscA is not defined.
*December 8, 2015*

**Calculus**

when she is x meters from the light, and her shadow has height y, then 2/x = y/24 -2/x^2 dx/dt = 1/24 dy/dt When she is 2m from the building (22 m from the light), -2/22^2 * 0.6 = 1/24 dy/dt dy/dt = -0.06 m/s
*December 8, 2015*

**Math**

assuming you mean the dot product, and the 2.3 should be 2,3 then we have 2*4 + 3*3 = 17
*December 7, 2015*

**physics**

well, you know the equation of the altitude of the trajectory is y = x tanθ - g/(2 v^2 cos^2θ) x^2 So, just solve for θ in 12000tanθ - 9.8/(2(800cosθ)^2) = 3000 θ = 14° Better check my math.
*December 7, 2015*

**Math**

So, finish the diagram. If the man enters the water at point C, x meters upstream from A, and lands at point D, y meters downstream from B, then we have distances of land: (d^2+x^2) water: √(x+y)^2+d^2) land: √(y^2+(2d)^2) The time it takes to cross the river is ...
*December 7, 2015*

**Math**

if you can't answer that one, you have not read anything about the sine function. Just as a hint, remember that sin^2 + cos^2 = 1
*December 7, 2015*

**Algebra**

since distance = speed * time, 6(b+s)=90 10(b-s) = 90
*December 7, 2015*

**st augustine/math**

5x + 10(50-x) = 350
*December 7, 2015*

**geometry**

find the slope m of the line joining the two points. All parallel lines have the same slope m All perp. lines have slope -1/m Check out the point-slope form of a line.
*December 7, 2015*

**Trig**

square the previous equations and add them up. Recall that sin^2θ + cos^2θ = 1
*December 7, 2015*