Saturday

May 28, 2016
Total # Posts: 40,868

**math( surface area )**

If the base has area B, then the prism's surface is 2B + 2*20(L+W) If L=W, then 2L^2 + 80L = 2400 L=W=20 See what you can do with L not equal W.
*April 4, 2016*

**Math**

since all the sides are magnified by a constant amount, the ratio of corresponding sides must be the same. So, 8/2 = x/4
*April 4, 2016*

**statistics**

1/6 * 1/6
*April 4, 2016*

**Math Algebra 2**

Aside from the typo where the c^2 gets lost, I'd just do it like this: m^2(1 - v^2/c^2) = m0^2 1 - (v/c)^2 = (m0/m)^2 (v/c)^2 = 1 - (m0/m)^2 v/c = √(1 - (m0/m)^2) To me, that makes it easier to see how the ratio of v to c is related to the ratio of the masses. ...
*April 4, 2016*

**simultaneous equation help**

From #1, y = (x^2-3)/(2x) so, in #2, 3x^2 - ((x^2-3)/(2x))^2 = 26 Or, assuming x≠0, (11x^4-98x^2-9)/(4x^2) = 0 (x-3)(x+3)(11x^2+1) = 0 x = -3 or 3 or complex values.
*April 4, 2016*

**Algebra**

If Diane takes x hours, 1/x + 1/(x-2) = 1/4
*April 4, 2016*

**math- geometry**

yes.
*April 4, 2016*

**Math (Rounding #s)**

It is 0.600 The 3rd decimal place is the thousandths. You need the two trailing zeros to specify the precision of the number.
*April 4, 2016*

**Math Algebra 2**

y = a(x-p)(x-q) using three different values of a will produce three different polynomials. Graphing them will produce parabolas that all cross the x-axis at the same two places (if at all), but are scaled differently.
*April 3, 2016*

**Trig**

recall that cos(a-b) = cosa cosb - sina sinb
*April 3, 2016*

**Math**

f = (2-3x)/(5-2x) f(a) = 3 when (2-3a)/(5-2a) = 3 2-3a = 15-6a 3a = 13 a = 13/3
*April 3, 2016*

**Math**

the pyramid has 1/3 the volume of the prism. Why wait for hours, when google can show you many discussions and formulas?
*April 3, 2016*

**maths help!**

know the density? mass = density * volume
*April 3, 2016*

**Math**

pyramid has 1/3 the volume of the prism.
*April 3, 2016*

**Maths**

tan^2(x/2) = (1-cosx)/(1+cosx)
*April 3, 2016*

**Maths**

sinx + sin3x = 4sinx cos^2x = 2sin2x cosx So, you have (2sin2x cosx - 2sin2x) --------------------------- (2sin2x cosx + 2sin2x) 2sin2x(cosx-1) --------------------- 2sin2x(cosx+1) = (cosx-1)/(cosx+1) Now take a look at the half-angle formula for tan(x/2)
*April 3, 2016*

**maths**

x^3-2x^2-13x-10 = (x+1)(x+2)(x-5) x^3-8^2 = (x+4)(x^2+4x+16) Looks like the LCM is just the product, since there are no common factors. Not sure what the minuscule has to do with it.
*April 3, 2016*

**Springville Middle School**

1/3 * pi * 15^2 * h = 7800
*April 3, 2016*

**Math**

h cot30 - h cot45 = 6
*April 3, 2016*

**Algebra**

{3,6,9,...}
*April 3, 2016*

**math**

clearly there were 3 times as many pears as oranges. So, 20 oranges.
*April 3, 2016*

**maths**

Is there a question somewhere in there?
*April 3, 2016*

**MATH**

if you are given only two of the dimensions, there is no way to determine the third. You need to know the volume, or the area, or a diagonal -- something to pin down that third dimension.
*April 3, 2016*

**cs203**

google is your friend. You might start here: http://stackoverflow.com/questions/14622371/how-do-i-print-a-binary-number-with-an-inputed-integer
*April 2, 2016*

**algebra**

or, since you have a point and a slope, you can just use the point-slope form: y-5 = 3(x-4)
*April 2, 2016*

**Math**

As long as the same dimension was used for rolling, the circumference is the same and the height is the same. So, the radii are the same, and both cylinders have volume π r^2 h.
*April 2, 2016*

**math**

okay. You know that all the s^(4x) and e^(-4x) stuff will zero out. So we need some quadratic stuff that will leave a particular solution. So, let's say that y_p is yp = Ax^2+Bx+C yp" = 2A yp" - 16yp = 2A - 16(Ax^2+Bx+C) So, we need -16Ax^2 - 16B + 2A-16C = 256x^...
*April 2, 2016*

**Mathematics**

(1-4)/(2-1) = -3/1 = -3 Clearly you need to plot the points and take a look at the line. + slopes are rising to the right - slopes are falling to the right
*April 2, 2016*

**Math**

clearly, 1275/1700 = ?
*April 2, 2016*

**Mathematics**

(1-3)/(-2-2) = -2/-4 = 1/2 Gotta watch those plus/minus values.
*April 2, 2016*

**math**

It's bad form to describe N(p) and then talk about x and y. Clearly, the N intercept is at -2818. What is p when N=0? Care to reconsider your answer?
*April 2, 2016*

**math**

Actually, it's the w-intercept in this case. At any rate, at the intercept, m(w)=0. That is, no money remains.
*April 2, 2016*

**algebra**

3/4 of 60 is 45 mi 45mi/9hr = 5 mi/hr what was she driving, a roller skate?
*April 2, 2016*

**Geometry**

h = 7√3, so each side is 14 A = (1/2)(14)(7√3) = 49√3 P = 3*14 = 42
*April 2, 2016*

**maths**

since (a+b)(a-b) = a^2-b^2 √3-√2 * (√3+√2)/(√3+√2) = (3-2)/(√3+√2) I assume by ig you mean log log(√3-√2) = -log(√3+√2)
*April 2, 2016*

**Calculus**

(x-3)^(2n)/4^n = (x-3)^(2n)/2^(2n) = ((x-3)/2)^(2n) So, as long as |(x-3)/2| < 1 it will converge.
*April 2, 2016*

**math**

Note that log_2(n) = 2*log_4(n) = 3*log_8(n) a = log_4(y) = (1/2) log_2(y) b = log_8(2y) = log_8(2) + log_8(y) = 1/3 + (1/3) log_2(y) b = 1/3 + (2/3) a 3b = 1+2a If logn = logm + 1, logn = logm + log10 = log(10m) so, n = 10m
*April 2, 2016*

**math**

20*8-20*5 = 20(8-5) = 60
*April 2, 2016*

**math**

8x + 5x = 260 find x, and then the amounts are 8x and 5x. Subtract to get your answer.
*April 2, 2016*

**Geometry**

Each leg is 10/√2, so P = 2*10/√2 + 10 = 10(1+√2) A = (1/2)(10/√2)(10/√2) = 100/4 = 25
*April 2, 2016*

**Math**

exactly.
*April 2, 2016*

**Math**

remember that distance = speed * time so, plug in your numbers.
*April 2, 2016*

**Math**

just multiply everything by 3!
*April 2, 2016*

**Math**

consider the sales tax. If it is 5%, the the final price is the retail price times 1.05, right? So, if our tax rate is r (expressed as a decimal), then the final cost of 70.75 is (1+r) times the sticker price. The tax amount is the final cost minus the sticker price: 70.75 - ...
*April 2, 2016*

**Math**

70.75(1-1/(1+r)) = 5.66 r = 0.0869 = 8.69%
*April 2, 2016*

**maths-help!!**

well, 240 = 4*60 so 2n can be any value from 0 to 58 so, n ...
*April 2, 2016*

**math**

(n*1.60)/(d*0.80) = (n/d)(1.60/.80) = (n/d)(2) so, the fraction is doubled. What percent increase is that? And it is not 200%!
*April 2, 2016*

**math**

(a*1.50)(b*0.80) = (ab)(1.20) so, the product increased by 20%
*April 2, 2016*

**math**

I can't quite picture your diagram, but 40 is 5/9 of the whole area. Maybe you can use that to get what you're after.
*April 2, 2016*

**math**

If each light consumes h watt-hours, then 4 lights running for n hours consume a total t of t = 4h*n Plug in your numbers. I can't figure out just what you're after.
*April 2, 2016*

**math - eh?**

Can you see how woefully incomplete your information is, if you want a solution?
*April 2, 2016*

**Math - incomplete**

why is x zero twice? Given your "table," I can fill in any numbers I want.
*April 2, 2016*

**maths**

S+H+J = 500 J = 3S S+33 = (5/6)(J-33) Oddly, I don't get integer solutions. Better check the problem and my setup.
*April 2, 2016*

**Computer science**

sure. That's why some computer folks are called systems analysts. Their basic software is called an operating system.
*April 2, 2016*

**Mathematics**

nope. (1-5)/(3-6) = -4/-3 = 4/3 better review the definition of slope.
*April 2, 2016*

**Mathematics**

did you plot the points? both have -3 for the x-coordinate, so the line is vertical. did you do the actual calculation? change in y divided by change in x? (-6 - -5)/(-3 - -3) = -1/0 is undefined.
*April 2, 2016*

**Math(PLZ HELP)**

#1 kg?? Really? That's over 2 lbs! Your paper clips must be a lot bigger than mine. #2 see #1 #3 ok #4 ok #5 ok #6 ok #7 a 15 ft border is added to each side, making both width and length 30 ft more. So, the new dimensions are 26+30 by 21+30 = 56 by 51
*April 1, 2016*

**Math**

Make a Venn diagram, and you can easily see that there are 70 students taking at least one of the classes, and thus 37 taking no class. Using the diagram, you can easily see how many students fit the questions; and thus the probabilities needed.
*April 1, 2016*

**Math (Real Analysis)**

epsilon-delta proofs use limits. abs(f) is continuous if f is continuous, because |f| = f if f>=0 |f| = -f is f<0 So, if the limit L exsists for f(x), it also exists for |f(x)|.
*April 1, 2016*

**math**

1 lb = 16 oz 3 lb = 48 oz You have given the number of lbs in 3 oz.
*April 1, 2016*

**trigonomentry**

no diagram, but I suspect that the Pythagorean Theorem can be used here.
*April 1, 2016*

**math**

no idea. There must be some other information here. If you know the height and the width, the length can be anything unless you also know the volume or area or a diagonal.
*April 1, 2016*

**math**

correct.
*April 1, 2016*

**math**

miles = 6 * minutes
*April 1, 2016*

**Dosage calculations**

1 tsp * 4.93 mL/tsp = 4.93 mL All that other stuff about number of days and number of doses is just noise.
*April 1, 2016*

**umd**

ok. Now what?
*April 1, 2016*

**Algebra 2**

font problems. Is that supposed to be sigma = 3.1? If so, just figure the mean, and find the maximum difference of each grade from the mean. Then divide that by 3.1 to get the number of std.
*April 1, 2016*

**math**

5.4ft/180m = 1.65m/180m = 1:109
*April 1, 2016*

**Math**

x changes by 1, y changes by -5 So, look for something like y = -5x Now adjust that so it fits.
*April 1, 2016*

**Math**

2340 + 100 - 50
*April 1, 2016*

**Math**

well, just plug in the x value and see whether you get the y value. For example, when x=0, 2*0 - 3 = -3 Nope, You want 3. Now try the others. One will work.
*April 1, 2016*

**Maths**

.40*30 = x(30+45) x = .16 or, since the volume has grown by a factor of 5/2, the concentration has been reduced by a factor of 2/5 to 16%
*April 1, 2016*

**trig**

Draw the triangle. sinθ = y/r cosθ = x/r tanθ = y/x In QII, y = 3 x = -4 r = 5 so, cosθ = -4/5 tanθ = -3/4
*April 1, 2016*

**Trig**

so, cos(x) = 1/7 and x is in QI or QIV so, x = 81.79 or 278.21 degrees no idea where you came up with your values for sin(x) and tan(x). ??
*April 1, 2016*

**Math**

you have to add x on each side, or 2x to both dimensions. So the perimeter is 2(5+2x+ 10+2x) = 30+8x
*April 1, 2016*

**math**

7:35
*April 1, 2016*

**Calculus**

draw your triangle You have the opposite leg=12 and the hypotenuse=13 So, the adjacent leg is √(169-144) = 5 cot(x) = 5/12
*April 1, 2016*

**Math**

If you mean ln(23x)+1 = 5 ln(23x) = 4 23x = e^4 x = e^4/23 If you mean ln(23x+1) = 5 23x+1 = e^5 x = (e^5-1)/23 Get used to being specific online.
*April 1, 2016*

**Math**

If x at 12%, then .12x + .15(5000-x) = 700
*April 1, 2016*

**Brief Calculus**

f' = 12x^2 - 18x - 30 Now use your Algebra I skills. (A) the critical numbers are where f'=0 (B) f is increasing where f' > 0.
*April 1, 2016*

**precalc**

Using the usual formulas, sin42°+sin18° = 2 sin30° cos12° since sin30° = 1/2, that is just cos12° = sin78° cosine means sine of the complement.
*April 1, 2016*

**Math**

if the drawing is 1 x 1.25 inches, then clearly each inch represents 20 feet.
*March 31, 2016*

**Math**

multiply all the numbers by 7 so that the largest is 42. 14:21:35:42 that should help.
*March 31, 2016*

**Mathematics**

so, if you plug in 12 for t, how do you get 12/3 = 15? You apparently did 12+3=15 better review what the operators mean.
*March 31, 2016*

**Mathematics**

well, it's bogus. It's already a whole number of dollars. Rounding to the nearest dollar doesn't mean anything unless there are some cents. $2200.51 rounds up to $2201 $2200.23 rounds down to $2200 $2200 rounded to the nearest thousand is $2000
*March 31, 2016*

**Math**

Draw a diagram. If the base of the rectangle is the segment (a,0) to (b,0) then the upper vertices are (a,4a) and (b,6-5b). Since it is a rectangle, the height is the same, so 4a = 6-5b. That is, b = (6-4a)/5 Now, the area is (b-a)(4a) = ((6-4a)/5-a)(4a) = 12a/5 (2-3a) This is...
*March 31, 2016*

**pr calc 11**

The quadratic formula works with all quadratics!! h = -0.09x^2+x+1.2 h(x) = 0 when x = [-1±√(1^2-4(-.09)(1.2))]/(2(-.09) = (-1±√1.432)/-0.18 = -1.09 or 12.20 Now, how does that answer the question? It means that when the water shoots out, it will hit ...
*March 31, 2016*

**pr calc 11**

just solve h(x) = 0
*March 31, 2016*

**algebra**

Since time = distance/speed, d/24 + 1/6 = d/30
*March 31, 2016*

**Math 142 (Pre-Cal) (Circles)**

looks good to me.
*March 31, 2016*

**math help pls pls pls**

correct.
*March 31, 2016*

**math help pls pls pls**

Assuming you know what the standard form is (highest degree first), then can you determine the degree of each term? Just add exponents of all the variables. what if two terms have the same degree? I have checked a few discussions, and none mentions that wrinkle. Check your ...
*March 31, 2016*

**algebra**

just sub in2x+2 for y x^2+3x-4 = 2x+2 x^2+x-6 = 0 (x+3)(x-2) = 0 ... or, without solving, you could just check each of the choices... duh
*March 31, 2016*

**Math**

If the sides in order of length are a,b,c then b = a+7 c = b+2 = a+9 a^2+b^2 = c^2 a^2+(a+7)^2 = (a+9)^2 a=8, b=15, c=17 I think you can take it from there, right?
*March 31, 2016*

**Hi need help with math**

what's all this shape stuff?
*March 31, 2016*

**algebra**

all those words! f(x) = |x| if -3 <= x < 1 4 if 1 <= x <= 8 Just plot each line, and mark off the sections you want. http://www.wolframalpha.com/input/?i=plot+[piecewise+[{{|x|,+-3%3C%3Dx%3C1},{4,+1%3C%3Dx%3C8}}]]
*March 31, 2016*

**College Algebra/pre-calculus**

since the value starts at $8000 and decreases by 7000 in 10 years ($700/year), the equation for the value is y = 8000 - 700x at x=6, y = 8000 - 4200 = 3800
*March 31, 2016*

**math**

a constant rate (slope) means a linear function. So, which of those is linear?
*March 31, 2016*

**Math**

of the 52 cards, how many are a heart or a 10?
*March 31, 2016*