Tuesday

October 6, 2015
Total # Posts: 34,328

**Math**

These questions usually seem to use a time signature of 4/4. So, a quarter note is one beat.
*September 30, 2015*

**Music**

#1 2/4 + 1/4 = 3/4 #2 6/16 = 3/8
*September 30, 2015*

**Math**

that would naturally be -3*30
*September 30, 2015*

**futher mathematics**

x^2+y^2 = 6x x^2-6x + y^2 = 0 x^2-6x+9 + y^2 = 9 (x-3)^2 + y^2 = 3^2 x^2+y^2-6x+14y+49 = 0 x^2-6x + y^2+14y+49 = 0 x^2-6x+9 + y^2+14y+49 = 9 (x-3)^2 + (y+7)^2 = 3^2
*September 30, 2015*

**trig**

h/12 = tan 30° now just solve for h.
*September 30, 2015*

**math**

If any of us knew the formula, do you think we'd be spending our time here instead of spending our money in Hawaii?
*September 30, 2015*

**Integers and Algebraiac Expression**

words, words, words! If you want to write an essay, post a problem for the English tutors. This is math, so -12/3 * (-8+ (-4)^2 - 6) + 2 You will find this problem in the related questions below, in various states of accuracy. But continuing with the solution, we have -4 * (-8...
*September 30, 2015*

**college algebra**

since time = distance/speed, If she started out with speed x, then 242/x + 351/(x+10) = 12
*September 30, 2015*

**math**

Look up the conversion factor for feet-to-meters. Then multiply that by 19/3.
*September 30, 2015*

**Equation find x xo tricky**

or, (x^x)√x = x(√x^x) divide by x^x √x = x x=1
*September 30, 2015*

**Advanced function**

If x is the place to finish, and t is the time, t(x) = 125+5x for x=1,2,3 t(x) = 140+(168-140)/(10-3) x for x>3 = 140+4x
*September 30, 2015*

**math,(integral calculus)**

recall the power rule: ∫ x^n dx = 1/(n+1) x^(n+1) + C for derivatives, multiply by power and lower it for integrals, raise the power and divide by it.
*September 30, 2015*

**MATH**

Set up a common denominator: 20x Then add things up: 5x(x+2) + 4x(5x) + (2x+1) ----------------------- 20x Assuming I parsed your fractions correctly... As written, without parentheses, they add up to 81x/20 + 1/2
*September 30, 2015*

**MATH**

consider that x^2+4x+4 = (x+2)^2 so, the area is [(x+2)/4]^2
*September 30, 2015*

**MATH**

just multiply by 4 (a square has 4 sides!), and you get (h-2k)/4
*September 30, 2015*

**math**

well, 48/6 = 8, so ...
*September 30, 2015*

**Word problem maths**

If the oldest boy's age is x, then (14 3/12)*21 = (14 2/12)*20+x x = 15 11/12
*September 30, 2015*

**Word problem**

(7 35/60)*37*6 = 1683 hrs 30 min
*September 30, 2015*

**Mathematics**

Peter's share is 3/8 So, If the goods are worth x, we have x(3/8)(2/3) = 8000 Now just find x.
*September 30, 2015*

**Math**

No way. His average score for the first 4 games was 11 points. No way could he raise his average to 12 by just scoring another 11! You need to set it up like this: 14+9+10+11+x = 5*12
*September 30, 2015*

**math 5th**

what does it matter whether it was on a quiz? It's just a math problem. Is there something unsatisfactory with my response?
*September 30, 2015*

**math 5th**

multiply by 3/3 and you have 3/5 * 3/3 = 9/15
*September 30, 2015*

**Math**

since all the angles are equal 10*2 = 2x^2-8x
*September 30, 2015*

**Southridge**

since the differences are 3,5,7,9 and the 2nd differences are all 2, you expect a quadratic. A little thought shows that y = x^2+1
*September 29, 2015*

**Algebra II**

suppose I said x*20 = x*a would you not say a=20? Same here. Two powers of x are the same if the exponents are the same. Or, if you've ventured into logs, then you have 20 logx = a logx divide by logx and you have 20 = a This only fails if x=1, since then logx = 0, and you...
*September 29, 2015*

**math**

10 chairs per row: GCF(50,60)
*September 29, 2015*

**Math**

correct.
*September 29, 2015*

**Math**

the range is always (-∞,+∞) (if you allow both positive and negative roots of even powers) just look at the graphs.
*September 29, 2015*

**Algebra**

Oh, please! Surely you know that 1/4 = 2/8! If not, you have no business taking algebra.
*September 29, 2015*

**Algebra**

1/8 (3d-2) = 2/8 (d+5) 3d-2 = 2(d+5) can you take it from there?
*September 29, 2015*

**crump elm**

Explain? Heck, I can't even figure out the question. Have you ever heard of proofreading?
*September 29, 2015*

**Geometry**

well, if the small angle is 5x, then 5x+6x+7x = 180 Now just find x and figure the angles.
*September 29, 2015*

**MATHS**

If an empty crate weighs x, and a full crate contains y kg of fruit, then x + y/2 = 14 x + y/3 = 12 Now just find x.
*September 29, 2015*

**Simultaneous equation xo difficult**

I don't think you will find any solutions where all three are nonzero. So, play around with x+y = 2 x^2+y^2 = 3 x^3+y^3 = 5 Then you can use the fact that x^3+y^3 = (x+y)(x^2-xy+y^2) = 2(3-xy) = 5 You should get somewhere with that.
*September 29, 2015*

**vector**

just integrate each term, to get -cos(t) i + sin(t) j and evaluate at the limits.
*September 29, 2015*

**Sphere help**

Not sure what you're asking. If the volume is increased by x% (a factor of (1+x/100), it's because the diameter was increased by ∛(1+x/100) ≈ (1+x/300) or x/3 %
*September 29, 2015*

**7th grade math help**

19/20 = 95/100 = 0.95
*September 29, 2015*

**Math**

If there are x $2 bags, then the rest (5-x) are $5.50 bags. So, 2.00x + 5.50(5-x) = 17.00
*September 29, 2015*

**Algebra**

max height occurs when x = -b/2a Here, that means max height is where x = -(24/9) / (-8/9) = 3 so, find y(3)
*September 29, 2015*

**math**

really? Just remember that < means less than <= means less than or equal, or not more than, or at most > means greater than >= means greater than or equal, or not less than, or at least So, now you can easily see that #1: x >= 45 #4: 8-2 <= x <= 10-2 try ...
*September 29, 2015*

**Math (Help)!**

as usual, draw a diagram. The track consists of two parallel stretches (the length of the rectangle, x) and a complete circle (the two semi-circular ends, diameter y). 2x + πw = 200 Now, unless you can provide some more info, you can't determine x and y. The track ...
*September 29, 2015*

**Algebra**

second runner will lose.
*September 29, 2015*

**Calculus**

let u = x^2 du = 2x dx and your integrand becomes 1/2 sin(u) du for the 2nd one, use integration by parts u = x du = dx dv = sin x dx v = -cos x ∫u dv = uv - ∫v du ∫ x sinx dx = -x cos x + ∫cos x dx
*September 29, 2015*

**geometry**

use the distance formula to find the length of the diameter. Then, C = πd
*September 29, 2015*

**math**

a = .23 r = .01 S = .23/(1-.01) = .23/.99 = 23/99
*September 29, 2015*

**Math**

you know that log(u) has domain (0,∞) and range (-∞,+∞) So, log(x-3) has domain (x-3)>0 or x>3. That is (3,∞) range is still the same. Adding 1 to ∞ makes no difference.
*September 29, 2015*

**algebra**

If the speeds are x and y then x+y = 500.3 y = x+2.8 Now just substitute in for y, figure x, then get y.
*September 29, 2015*

**Math**

(y^4)(y^3) = y(4+3) = y^7 Powers are just shortcut for multiplication (y^4)(y^3) = (y*y*y*y)(y*y*y) = y*y*y*y*y*y*y = y^7
*September 29, 2015*

**Math**

let's see what they told you: r+b+a = 36 b-2 = 3(r-2) a+8 = 2(b+8) Now just solve for the ages.
*September 29, 2015*

**calc 2**

As you know, Newton's law says that your Temperature function is T(t) = 70 + 280e^-kt So, just solve for k in 70 + 280e^-20k = 210 then solve for t in using T(t) = 155.
*September 29, 2015*

**maths**

you can do it in base 10 because you know your multiplication table. To do it in base 12, you need to use a base-12 table. So, get out your pencil and paper and make one up. Or, if you have a unix system handy, run bc and use ibase=12 and obase=12. Then just enter your base-12...
*September 29, 2015*

**Math**

cis2x = (cis x)^2 cis3x = (cis x)^3 so, the quotient is 1/cis x
*September 29, 2015*

**Algebra**

2n + 3n-4
*September 29, 2015*

**algebra**

let u = x^(1/5) The equation then becomes u^2-8u+16 = 0 (u-4)^2 = 0 u = 4 so, x^(1/5) = 4 x = 4^5 = 1024
*September 29, 2015*

**Physics**

dat no de fomla R^2 = A^2 + B^2 Surely you could have looked that up in less time than posting here and waiting for a response...
*September 29, 2015*

**College Algebra**

-2^-3(xy^3)^-2 = -1/(8x^2y^6) x^-1y^-3 = 1/(xy^3) now divide (multiply by the reciprocal) and you have -1/(8x^2y^6) * xy^3 = -1/(xy^3) or, you can just do it like this -2^-3 (xy^3)^-2 (xy^3) = 1/8 (xy^3)^-1 = -1/(8xy^3)
*September 29, 2015*

**College algebra**

since you have no final numbers to work with, it means that your final formula will involve "h" standing for the height. See the problem solved at http://www.jiskha.com/display.cgi?id=1443498508 When you say you figured out the area, what did you do?
*September 29, 2015*

**College Algebra**

browsers override your text formatting. I think you meant 1/(4x-12) - 1/(2x-6) = 1/(x^2-3x) Factoring the denominators, you have 1/4(x-3) - 1/2(x-3) = 1/x(x-3) Clearly the LCD is 4x(x-3). So, using that LCD, you have in the top 1(x) - 1(2)(x) = 1(4) x-2x=4 x = -4 You can ...
*September 29, 2015*

**College Algebra**

You can always use wolframalpha.com to verify your work. For example, http://www.wolframalpha.com/input/?i=5x^2-10x%2B6%3D0 You got 10±√-2 That is clearly wrong. The formula states x = [-b±√(b^2-4ac)]/2a = [10±√(100-120)]/10 = (10±...
*September 29, 2015*

**College Algebra**

so, what don't you know abouth the formula? You have a = 5 b = -10 c = 6 Now just plug them into the formula.
*September 29, 2015*

**College algebra**

b = 2h-7 A = 1/2 bh = h(2h-7)/2
*September 28, 2015*

**ctu**

12474(1+r)^3 = 14001.00 r = 0.039 = 3.9%
*September 28, 2015*

**College Algebra**

If the smaller radius is r, then r+8 = 3r
*September 28, 2015*

**College Algebra**

(2+3i)^3 = 2^3 + 3*2^2*(3i) + 3*2*(3i)^2 + (3i)^3 = 8 + 36i - 54 - 27i = -46+9i
*September 28, 2015*

**Physics**

as you know, the range is r = (v^2 sin2θ)/g Now just plug in your numbers
*September 28, 2015*

**algebra**

I think you meant (6x+1)-(3x+4) = 6x+1-3x-4 = 3x-3 using 3: 3(3)-3 = 6 Yiur asnwer was right, but your grouping of values without parentheses was wrong. As it was written, you'd have 6(3)+1-3(3)+4 multiplication comes first, unless otherwise specified using parentheses: 18...
*September 28, 2015*

**Physics kinematics**

you know the range is given by R = v^2/g sin2θ so, plugging in your numbers, 36^2/9.8 sin2θ = 72
*September 28, 2015*

**Physics**

well, using your trajectory equation y = tanθ x - g/(2 (v cosθ)^2) x^2 just plug in your numbers and solve for v: 0.9657x - 9.4795/v^2 x^2 = 2.4 and if x=31, you have v = 18.19 m/s
*September 28, 2015*

**algebra**

double eq #2 and you have 2x-5y = 8 2x-6y = -2 Now subtract #2 from #1 and you eliminate x: y = 10 Now you can use either equation to find x.
*September 28, 2015*

**Geometry**

yes. consider the consecutive interior angles.
*September 28, 2015*

**Algebra**

x+4 = √5 Could you do it if it were x+4 = 12? If so, do this the same way. Don't let that √5 scare you -- it's just a number.
*September 28, 2015*

**math**

Apply your methods and see whether you can arrive at the answer from Wolframalpha.com: http://www.wolframalpha.com/input/?i=y%22%2By%27%3Dx%2Bsin%282x%29
*September 28, 2015*

**Geometry**

A carpenter cut the top section of a window frame with a 37-degree angle on each end. the side pieces each have a 50 degree single cut at their top sides. Will the side pieces of the frame be parallel?
*September 28, 2015*

**Integration need help**

recall that sinA cosB = [sin(A+B)+sin(A-B)]/2 so, your integrand is just 1/2(sin11x + sinx) dx which is easy, right?
*September 28, 2015*

**Math**

ok - now what?
*September 28, 2015*

**AP Physics**

s = 6.9(157) + 1/2 a(157^2) = 2700 Now you can find a, and then v = 6.9+157a = 6.9+(2(2700-6.9*157)/157^2)(157) = 27.5 m/s
*September 27, 2015*

**Science**

No, it's more like an Oscar Meyer wiener. Kinda like you.
*September 27, 2015*

**math**

for what?
*September 27, 2015*

**Quick math help**

I disagree. A coefficient near 1 indicates that the data points lie very close to the best-fit line. So, using the line should provide useful approximations. The fact that we're even talking about a line of best fit indicates that the data are linear, or close to it. ...
*September 27, 2015*

**Math**

No way to tell the number of grams, since we know nothing about the solute. But in any case, the mass of solute is not changed by adding some water.
*September 27, 2015*

**algebra**

If the tens digit is 2x, the units is 3x. Then we have 10(3x)+2x = 10(2x)+3x + 27 x=3 The n umber is 69 96 = 69+27
*September 27, 2015*

**Physics, math**

well, just plug in the values of the trig functions, and you have 1.2 = 4.6*1.192 - 4.9*21.16/(0.413x^2) Now just collect the constants and solve for x.
*September 27, 2015*

**math**

well what's 25% of 500,000 mg?
*September 27, 2015*

**Calculus**

the chain rule is always necessary. It just happen s that dx/dx = 1, so it doesn't enter into the complexity. Suppose you had x^3 + y^3 + u^2 = uv^2 Then you'd have 3x^2 + 3y^2 y' + 2u u' = u' v^2 = 2uv v' Whenever you take a derivative, you have to ...
*September 27, 2015*

**Calculus**

Your second line should be (via the chain rule!) y" = [(y^2)(-2x)-(-x^2)(2yy')]/y^4 Now plug in -x^2/y^2 for y' and you should get the right result.
*September 27, 2015*

**Tertiary**

(a+b)^2e^-2x=a^2-b^2 divide both sides by a+b: (a+b) e^-2x = a-b (a+b)/(a-b) = e^2x a+b = ce^x a-b = ce^-x and the rest follows.
*September 27, 2015*

**Tertiary**

sinh x = (e^x - e^-x)/2 So, now you have e^x - e^-x = 2tan y e^2x - 1 = e^x * 2tan y e^2x - 2tany e^x - 1 = 0 Now use the quadratic formula to get e^x = [2tany ±√(4tan^2y+4)]/2 = tany±√(tan^2y+1) = tany±secy x = ln(tany±secy) Pick the ...
*September 27, 2015*

**fundamentals math**

without a Z table there is no way to do this stuff. Not unless you can calculate the normal distribution stuff by hand. There may be a chance that they will provide a few Z scores at test time, and if so, then you can interpolate. Otherwise, check your class materials and ...
*September 27, 2015*

**fundamentals math**

you can play around with Z table stuff here: http://davidmlane.com/hyperstat/z_table.html
*September 27, 2015*

**Math**

make sure you know what the general form is. Then expand this to get x^2-10x+25 = 5 Now just rearrange terms to place in general form.
*September 27, 2015*

**college algebra**

Or, reason like this: after 1 hour, the freight train is 60 miles ahead. Since the passenger train goes 20 mi/hr faster, how long will it take to make up the 60 miles?
*September 27, 2015*

**college algebra**

since distance = speed * time, 60(t+1) = 80t Now just find t. That's the time traveled by the faster train.
*September 27, 2015*

**Math**

x + .75x = 1425 x is the larger paycheck.
*September 27, 2015*

**Math**

just turn all those words into algebra: If there are x mg of vitamin C in a glass of apple juice y mg in a glass of orange juice then consider the amount of vitamin C as described above: x+y = 180 4x+3y = 637.4 now just find x and y It could have been worse; the glasses might ...
*September 27, 2015*

**Precalculus**

If y = ax^2+bx+c, then we can plug in the points and get 0a+0b+c = 5 a+b+c = 2 9a+3b+c = 2 y = x^2-4x+5 Or, noting the symmetry about x=2, we know that y = a(x-2)^2 + k y(0) = 5, so 4a+k = 5 y(1) = a+k = 2 so, a=1,k=1 y = (x-2)^2+1
*September 27, 2015*

**calculus**

recall that if u = secx, u' = secx tanx You have ∫ secx dx Turn that into a fraction by multiplying by (secx + tanx) and you have ∫ secx(secx+tanx)/(secx+tanx) dx Now, if u = secx+tanx, du = secx tanx + sec^2 x and your integral now becomes ∫ du/u = lnu...
*September 27, 2015*

**Math- Please help**

#1 g(x) = f(x-3) = x-3 #2 g(x): stretch y by 5: 5f(x) down 3: 5f(x)-3 x reflect: -(5f(x)-3) = 3 - 5f(x) g(x) = 3 - 5x^2 #3 g(x): shrink y by 4: (1/4)f(x) right 1: (1/4)f(x-1) up 2: (1/4)f(x-1)+2 g(x) = (1/4)|x-1|+2 #4 g(x): y stretch 3: 3f(x) up 2: 3f(x)+2 right 8: 3f(x-8)+2 g...
*September 27, 2015*

**Math**

that would be 2.46 std below the mean, or 78-2.46(4.6)
*September 27, 2015*

**Physics**

Maximum range is achieved at a 45° angle of elevation. Just use your equation of motion to get the range. If you have forgotten the relevant formulas, read a nice discussion here. https://en.wikipedia.org/wiki/Trajectory Then add a term of 250 to adjust the equation. Hmmm...
*September 27, 2015*