Tuesday

October 6, 2015
Total # Posts: 34,328

**Maths**

just multiply the tops and bottoms: x y^2 z^2 ----------------- yz z y add the powers of each variable: x y^2 z^2 ------------ y^2 z^2 Now cancel like factors, and you wind up with just x
*September 14, 2015*

**Calculus 1**

√(x+h)-√x ------------ h (√(x+h)-√x)(√(x+h)+√x) -------------------------- h(√(x+h)+√x) (x+h)-x ------------------- h(√(x+h)+√x) h --------------------- h(√(x+h)+√x) The h's cancel, and you have 1/(&#...
*September 14, 2015*

**Calculus 1**

just use the difference quotient, and recall how to "rationalize" expressions involving roots: √x - a = (√x-a)(√x+a)/(√x+a)
*September 14, 2015*

**Calculus 1**

I guarantee that your text has this very problem in it. It starts out as the limit of √(x+h)-√x ------------ h That's hard to handle, but if you multiply top and bottom by √(x+h)+√x things will drop out nicely when you take the limit.
*September 14, 2015*

**Calculus 1**

The slope of the tangent for any x is f'(x) = 2x-1 So, you want the line y-f(3) = f'(3) * (x-3)
*September 14, 2015*

**Calculus 1**

x^2-3x+10 is never zero, so there are no VAs. You found the roots, where y=0.
*September 14, 2015*

**Calculus 1**

c'mon, guy, this is just Algebra II. vertical asymptotes where the denominator is zero and the numerator is not zero. Horizontal asymptotes where x is huge. When x is huge huge huge, only the highest powers matter. So, toss out everything else in the top and bottom and see...
*September 14, 2015*

**India international, Mathis trigonometry**

Clearly you have a typo, since cosine is never greater than 1. secθ-tanθ = 4 Since we want cosθ at the end, let's change stuff now: 1/cosθ - sinθ/cosθ = 4 (1-sinθ) = 4cosθ 1-2sinθ+sin^2θ = 16-16sin^2θ 17sin^2θ-...
*September 14, 2015*

**Maths**

Why not get rid of the fractions to start with? Just multiply everything by 5: 5(y+4) = 3(x-1) 5y+20 = 3x-3 Now just rearrange stuff.
*September 14, 2015*

**math**

acar? you mean away? 1000m / (2.5 m/s) = 400s
*September 14, 2015*

**Math**

oops. 1/3 pi r^2 h
*September 14, 2015*

**Math**

bottom half is a cone. r=3, h=6 v = 1/2 pi r^2 h Now just plug in the numbers
*September 14, 2015*

**Geometry**

those two quantities are points, not lines. the only difference between them is their location. I think you want the distance between the points. That is, the length of the line segment joining them. That would be √((6-(-4))^2+(1-3)^2) = √(10^2+2^2) = √104 = ...
*September 14, 2015*

**Math**

BA has initial point B. So, you want a ray with initial point B pointing the other way. That would, of course, be BD.
*September 14, 2015*

**Math**

since KP is in both planes, it will be the intersection. You are correct
*September 14, 2015*

**math**

3 reds, 12 total So, P(red,red) = 1/4 * 1/4
*September 14, 2015*

**adv algebra**

surely if you have discussed probability at all, you must have learned that it is always a number between 0 and 1.
*September 14, 2015*

**Word problem**

42
*September 14, 2015*

**math**

Clearly, it is D. You use random samples to estimate properties of the whole population.
*September 14, 2015*

**Math**

If Michael takes x, hours, then 1/x + 1/(x-2) = 1/9 Now just find x, and then x-2.
*September 14, 2015*

**Math**

ok on the first. 9 x (7-16) + 9 9 x (-9) + 9 -81 + 9 -72
*September 14, 2015*

**Math**

If the 7,8,9% amounts are x,y,z, respectively, then we have x+y+z = 23000 .07x + .08y + .08z = 1800 z = x/2 Just solve that for your answers. Trés simples!
*September 14, 2015*

**math**

if you know how the average is calculated, the solution should be clear. If not, then review the steps for the calculation, and just plug in your numbers.
*September 14, 2015*

**math**

half as much as for 4 servings, since 2 is half of 4.
*September 13, 2015*

**Business**

to tutor at the school
*September 13, 2015*

**Business**

Brianna is organizing a group of staff from her engineering company to provide Saturday afternoon tutoring for students at the nearby middle school. In order for her group of staff to remain stable, what is the optimal number of people she should recruit to help? a- 7 b-5 c-3 ...
*September 13, 2015*

**Business**

thank you
*September 13, 2015*

**Business**

Is your work place an example of a primary or secondary group?
*September 13, 2015*

**algebra**

since time = distance/speed, 18/(x+6) + 16/(x-6) = 5 Now just find x.
*September 13, 2015*

**Maths**

I'll do one, you try the other. y = -2x/7 - 6 multiply by 7 to clear the fraction: 7y = -2x - 42 Now move everything to the left side: 2x + 7y + 42 = 0
*September 13, 2015*

**Math**

f+s=33 f+x = 4(s+x) clearly, f > 4x now, since f/s decreases as both grow So, f > 24, meaning s < 7 You want f to be close to 4s now, so try s=6, f=27 In one year, s=7, f=28 Looks like 1 is the smallest value.
*September 13, 2015*

**math - age problem**

v-3 = 3(p-3) v = 2p v+p=18 clearly Vin is 12 and Paul is 6 You can do that without the first condition at all.
*September 13, 2015*

**math**

You want a circle of radius a inside the circle of radius r, so that pi r^2 = 2pia^2 2a^2 = r^2 a = r/√2
*September 13, 2015*

**Pre-calculus- URGENT**

Think of the unit circle (or any circle centered at (0,0) for that matter). At any angle θ, tanθ = y/x r^2 = x^2+y^2 Complex number a+bi is plotted in the x-y plane, so r^2 = 8^2+√3^2 = 64+3 r = √67 tanθ = √3/-8 That is in QIV (where x is ...
*September 13, 2015*

**math**

a^3-b^3 = (a-b)(a^2+ab+b^2) So, using a=x+y and b=x-y (x+y)^3 - (x-y)^3 = ((x+y)-(x-y))((x+y)^2+(x+y)(x-y)+(x-y)^2) = (2y)(x^2+2xy+y^2+x^2-y^2+x^2-2xy+y^2) = (2y)(3x^2+y^2)
*September 13, 2015*

**mathematics**

You want (1+r)^5 = 2 1+r = 2^0.2 r = 2^0.2 - 1
*September 13, 2015*

**Maths urgent**

the interior angles of an n-gon are (n-2)(180)/n So, you have ((2n-2)/(2n)) / ((n-2)/n) = 5/4 Now just solve for n.
*September 13, 2015*

**Math- Algebra**

The tunnel is 7 trains long. So, 8 train lengths must pass through the tunnel in 2 minutes. The speed is thus 8(600m)/(120s) = 40 m/s
*September 13, 2015*

**Tholulwazi**

acceleration of 2m/s^2 means that the velocity increases by 2m/s every second. So, clearly, since v = at, v = (2m/s^2)(10s) = 20m/s Keep track of the units! They will give clues as to the required calculations.
*September 13, 2015*

**Intermediate math**

These are just the difference of 2 cubes. a^3-b^3 = (a-b)(a^2+ab+b^2) So, the first one is x^3y^6-64 = (xy^2)^3 - 4^3 = (xy^2-4)((xy^2)^2+(xy^2)(4)+4^2) = (xy^2-4)(x^2y^4+4xy^2+16) Do the other in like wise. It comes out very simple. You can use wolframalpha.com to check your ...
*September 13, 2015*

**Difficult algebriac word problem**

danged if I know. Can't quite make sens of your strange syntax. and at night it became double, what became double?
*September 13, 2015*

**mathematics**

You have x^2 + (y+f)^2 = f^2-1 These are circles with center at (0,-f). Clearly the radii of these circles are orthogonal to the curves, and that is the family of lines that pass through (0,-f): y+f = mx
*September 13, 2015*

**Math: Geometric Progression**

a+ar+ar^2 = 70 5ar-4a = 4ar^2-5ar GP is 10,20,40 AP is 40,100,160
*September 13, 2015*

**Math**

a - 1/a = 2 a^2-2a-1 = 0 a = 1±√2 Now just square that and you get 8
*September 13, 2015*

**math**

1.2s (1 - 1/5 - 0.4) = 6/5 s (2/5) = 600 12/25 s = 600 s = 1250
*September 12, 2015*

**Algebra 2**

I find it simpler just to clear the fractions (2/3 - x)/(2/3 + x) multiply top and bottom by 3 and you have (2-3x)/(2+3x) Your final answer is clearly wrong, since you have 3x-2 top and bottom, making the value just -1.
*September 12, 2015*

**Algbra 2**

enter your polynomials at http://calc101.com/webMathematica/long-divide.jsp and see all the details of the division. Or, do synthetic division, using the value of -1 for the root.
*September 12, 2015*

**Calculus 1**

These are a bit tedious, but not hard. I'm sure your book has examples just like them. Give it a go, and come back if you get stuck. Show what you did. Just recall that √(1-2(x+h)) - √(1-2x) can be "rationalized" by multiplying top and bottom by &#...
*September 10, 2015*

**Calculus 1**

yes. I forgot that it said "using limits". Sorry. It's just back to basics.
*September 10, 2015*

**Calculus 1**

v(t) = ds/dt, so (a) v(t) = 2t-8 (b) v(t) = -2/t^3 Just plug in your numbers.
*September 10, 2015*

**Maths**

0.375 grams? What, one kernel per bag? Anyway, just multiply to get the total weight needed.
*September 10, 2015*

**math**

sinθ = 2.1/3.8 distance from wall can be found using either x = 3.8 cosθ or x^2 = 3.8^2 - 2.1^2
*September 10, 2015*

**algebraII**

It says "the number is twelve more than one hundred times the hundred digit" The number is 100z+10y+x. So, you want 100z+10y+x = 100z+12 Now plug in your values and solve for x.
*September 10, 2015*

**Math algebra**

Of course you have some idea. Surely you can graph y = 2x+8 Draw that line, but stop at x=-2 Then between x = -2 and x=3, draw the graph of y = 5-2x Then for x beyond 3, draw the graph of y = -2. Just take it slowly and do one step at a time.
*September 9, 2015*

**Algebra**

66/6
*September 9, 2015*

**Physics ( Thickness of a Spherical Shell)**

The volume of the shell and its interior is v = 4/3 πr^3 = 4/3 π * 2^3 = 33.510 cm^3 That means that the mass (volume*density) is m = 33.510cm^3 * 0.5g/cm^3 = 16.755g So, if the interior radius of the shell is r, then the volume of the actual shell material is v = 4/...
*September 9, 2015*

**algebra 2**

find a line that fits the observed data closely. Read up on least-squares fitting.
*September 9, 2015*

**math **

the tickets to a concert cost $10 for the lower level and $5 for the upper level. A total of 35000 tickets were sold for a total amount of 325000. how many lower level tickets were sold.
*September 9, 2015*

**Math**

assuming no leading zeros, there would be 6 * 6 * 5 candidates.
*September 9, 2015*

**Math**

geez. Just replace every y with 5: 4*5^2 = 4*25 = 100
*September 9, 2015*

**algebra**

I get 12/175 How far did you get?
*September 9, 2015*

**Math**

Yes. Could you not check your answer to see whether it fit the equations? That's faster than posting here and waiting for an answer.
*September 9, 2015*

**MATH HELP**

1A 2C 3B 4D
*September 9, 2015*

**Physics**

A solar still is used to make fresh water from salt water by evaporation. Assume that during a summer day that 1000 BTU/ft sq of solar energy falls on the surface of the salt water. Determine how many inches of water are evaporated in 30 days. Assume that 1040 BTUs is needed ...
*September 9, 2015*

**algebra II**

I'd say that since 1g of water is 1mL, you want 30/v = .085/1 v = 353 mL Of course, I might be wrong.
*September 9, 2015*

**math**

If the distance from the airport to the offices is x, then he drove 250-x miles. Since time = distance/speed, (250-x)/45 + x/120 = 3 Now just solve for x
*September 9, 2015*

**Pre-Calc**

that is correct. The question is poorly worded, though.
*September 9, 2015*

**algebra**

Try this: (x+y)(x-y) = 25(x-y) x+y = 25
*September 9, 2015*

**Algebra (PS)**

Reiny, you're forgettin' the vig!
*September 9, 2015*

**college algeb**

∛(3x^2) * √(2x) = 6throot ((3x^2)^2 * (2x)^3) = 6throot(72x^7) √(3+2√2) * √(3-2√2) = √((3+2√2)(3-2√2)) = √(9-8) = 1 6throot(12) / (√3*∛2) = 6throot(12) / 6throot(3^3 * 2^2) = 6throot(12/36) = 1/6throot(3) ...
*September 9, 2015*

**Algebra**

-12/3 * (-8 + (-4)^2 - 6) + 2 -4 * (-8+16-6) + 2 -4 * 2 + 2 -8 + 2 -6 Just follow the usual order of evaluation.
*September 9, 2015*

**science**

well, if the half-life is n years, you want t where (1/2)^(t/n) = 0.03
*September 9, 2015*

**Pre-Calc**

correct
*September 9, 2015*

**Check my answers MATH**

any terminating decimal is rational any repeating decimal is rational So, their product is also rational Hence (D) You got #2 right, so I'm surprised you missed #1.
*September 9, 2015*

**Global school**

since distance = speed * time, you have 2d = (340 m/s)(0.5 s) Now just find d.
*September 9, 2015*

**algebra**

500(48/120)(3/5) = 120
*September 9, 2015*

**Math**

Hard to tell, looking at your text. try using the more usual notation for online text. Something like (3/2)*(3/2) - 5/(10-6) or something for using fractions.
*September 9, 2015*

**Math**

24/8 + 6*9^2 = 489 B looks good to me.
*September 9, 2015*

**Math**

Clearly, a 50cm square stone is the largest that will evenly tile both dimensions. So, how many of those will fit in each direction?
*September 9, 2015*

**pre-calc @Damon**

Good work, Damon, but the slope was in fact -2.
*September 9, 2015*

**Intermediate algebra**

Just like any other equation. Isolate the variable you want. If you had I = 5t, would that be a problem? No. Well, you have I = (pr)t t = I/(pr)
*September 9, 2015*

**PHYSICS**

(28π cm/rev) * (2020 rev/min) = 56560π cm/min
*September 9, 2015*

**Math 10**

the rules for logs work for any base, so assuming base 4 throughout, log(x*(3x-5)) = log(x) + log(3x-5)
*September 9, 2015*

**Science**

Sorry. I guess I missed the list...
*September 9, 2015*

**Math**

A clearly, f(1) = 0 B and f(0) = 3 C So, f(x) = 3 - 3x Since f(0) = 3, the function will be mx+3 Just find m such that m+3 = 0 since f(1) = 0
*September 9, 2015*

**maths**

Divide the fence equally among the lengths and widths. So, the field is 5000x2500
*September 9, 2015*

**Math word problem**

Counting the cents, we have 10(22) + 1(5*22) = ?
*September 9, 2015*

**maths**

recall the distance formula: 2^2 + h^2 = 6^2
*September 9, 2015*

**Math word problem**

10 + 6*10 = 70
*September 9, 2015*

**Geometry**

AD = 2x+8
*September 9, 2015*

**math**

well, just plug in a 5 for each x: f(5) = (5^2+7)/(5^3+5*5) = 16/75
*September 9, 2015*

**math**

If Charles is now c and Seth is s, Charles was Seth's age c-s years ago, so c = 2(s-(c-s)) c+s = 100 Hmmm. I don't get an integer solution. Check my math.
*September 9, 2015*

**Math**

.40x + .18*50 = .24(x+50)
*September 9, 2015*

**math**

1st step might be to change them all to decimals. Then it will be clear.
*September 9, 2015*

**Algebra**

clearly, it is d = 8 - (1/2)w
*September 9, 2015*

**algebra**

yes, -0.4 is between -0.5 and -0.3 Just draw your number line, and mark the points.
*September 9, 2015*

**math**

well, they are both tenths: 3/10 and 5/10 Now you can simplify
*September 8, 2015*

**Math**

4 5/8 = 4 + 5/8
*September 8, 2015*