Tuesday

July 26, 2016
Total # Posts: 42,093

**math**

well, how far does the hare go? distance = speed * time
*June 12, 2016*

**math**

probably the latter, as the previous post used half-angle formula. So, eku, I guess that gives a clue to this one, too, eh?
*June 12, 2016*

**maths**

x+y+z = 26 y = 3x You want minimal x^2+y^2+z^2, so check out a few possibilities: x y z ∑*^2 1 3 22 488 2 6 18 332 3 9 14 208 ... I think you can figure it out.
*June 12, 2016*

**math**

use your half-angle formula: tan(A/2) = (1-cosA)/sinA you can easily find cosA, and then just plug and chug.
*June 12, 2016*

**Maths**

Draw the unit circle. Draw a right triangle in standard position (right angle on the x-axis). Now label the sides. The hypotenuse is 1 The height is x Let angle A be at (0,0) So, sin(A) = x/1 = x That is, A = sin^-1(x) csc(A) = 1/sin(A) = 1/x So, A = csc^-1(1/x)
*June 12, 2016*

**math**

so, what's the problem? Get out your protractor and ruler.
*June 12, 2016*

**math**

upstream time is m/(r-s) downstream time is m/(r+s)
*June 12, 2016*

**Math**

something is messed up. I suspect a typo. In particular, I think 4.6 cakes will take a lot more than 3/5 lb of flour, unless they are very small cakes. Hmmm. 2/3 lb is about 3/5 cup. I know I can't make 4 cakes with that much flour!
*June 12, 2016*

**Math**

suppose you know how much you need to make 3 cakes. To make one cake, you just divide by 3, right? So here, just divide by 4 3/5. (2/3)/(4 3/5) = (2/3)/(23/5) = 2/3 * 5/23 = 10/69 All fractions work the same way.
*June 12, 2016*

**Algebra**

Usually people don't talk about "prime factors" of polynomials, but a complete factorization should do the job. Here are a few: a. 2a^2 - 2b^2 = 2(a^2-b^2) = 2(a-b)(a+b) b. 6x^2 - 6y^2 = 6(x^2-y^2) = 2*3(x-y)(x+y) c. 4x^2 - 4 = 4(x^2-1) = 2*2(x-1)(x+1) d. ax^2 - ...
*June 12, 2016*

**Physics**

so, did you draw the path? where did you end up? Hint: label the start (0,0) Distance covered is just the sum of all the line segments. Final displacement is found using the normal distance formula, which is just the Pythagorean Theorem.
*June 12, 2016*

**Trigonometry**

nothing to do but convert to x-y form, add them up, and then convert back. Luckily, they can be treated as complex numbers, making the job easier, using polar form. And, you can let wolframalpha.com do all the work (or any other handy calculator you know). You can check your ...
*June 11, 2016*

**Mathematics**

Nope. The A+B+C=180 Note that the sides AC = b AB = c Use the law of cosines to get a^2 = b^2+c^2-2bc cosA Now, having a, you can use the law of sines to get A: sinA/a = sinC/c
*June 11, 2016*

**Math - Year 10 - Simult. equations**

you know that 4y = -3x, so use that in 16x^2 + 16y^2 = 400 16x^2 + (4y)^2 = 400 16x^2 + 9x^2 = 400 and I think you can take it from there, right?
*June 11, 2016*

**pre-algebra**

Interesting. As a position relative to the surface, the value is -550. But, as you say, the depth is indeed 550 ft. "Depth" carries with it an implied negative value. I'd check to see just how they want you to interpret positive and negative quantities.
*June 11, 2016*

**Math**

best bet is to convert all to decimals. The it will be easy. SO, 2/3 = 0.6666 0.2 = 0.2000 and so on
*June 11, 2016*

**Algebra**

(a+b)(a+b) Now just expand that us usual
*June 11, 2016*

**maths**

if two polynomials have the same roots, one is a multiple of the other. So, x^2+px+q = 2(x^2-(5/2)x-(3/2)) so, p = -5/2 and q = -3/2
*June 11, 2016*

**maths**

If the roots are p and q, then we have pq = k Since p = 1/q, pq = 1 So, k=1 x^2-5x+1 has roots (5±√21)/2 I leave it to you to verify that the two values are reciprocals.
*June 11, 2016*

**Logarithm**

Your observation appears correct; the right side is 1/√(27^2) (3^x)^3 = 3^(3*x) = 3^(3x) 9 = 3^2, so 9*3^(3x) = 3^2 * 3^(3x) = 3^(3x+2) Now, on the right, for any value n, √(n^2) = n, so we have 1/27 = 3^-2 So, we want x such that 3^(3x+2) = 3^-2 3x+2 = -2 3x = -4 ...
*June 11, 2016*

**Maths**

Actually, the number is 58.
*June 11, 2016*

**Algebra**

reciprocals of equals are equal. Unless the equals are zero...
*June 11, 2016*

**Calculus**

as usual, for a given perimeter (sum), a square has maximum area (product).
*June 10, 2016*

**math**

(50*60 + 25*56 + 25x)/(50+25+25) = 58 now solve for x
*June 10, 2016*

**math (significant digits)**

you only have one s.d. .03 + 0.2 = .23 which becomes 0.2
*June 10, 2016*

**math**

that looks better.
*June 10, 2016*

**math**

since they are of equal weight, their average is just the arithmetic average of the two scores: 87 Why do I suspect that the problem was misstated?
*June 10, 2016*

**Math**

ar^2 = 4 So, you want to know a^5 r^10 = (ar^2)^5 = 4^5 = 1024
*June 10, 2016*

**Math**

a 1-cm thick layer of water has a volume of π*35^2 cm^3 = 3.848 L So, you want to know how long it takes to drain 20cm = 76.97L 76.97L ÷ 10L/hr ≈ 7.7 hr
*June 10, 2016*

**maths**

what does a circular pool is 300 mean?
*June 10, 2016*

**maths**

If 1/3 were bad, then 2/3 were good. So, he made (5 1/4)*(3/4)(712)(2/3) =
*June 10, 2016*

**math**

Just do the division. The remainder is (m-3)y + (n+3) To be divisible, the remainder must be zero, so that means m=3 and n = -3. Check: y^4 + 3y^3 + 2y^2 - 3y - 3 = (y^2-1)(y^2+3y+3)
*June 10, 2016*

**Algebra**

You must group terms with like exponents. For example, #20 3x^2 – [7x- (4x – x^2) + 3] = 3x^2 - [7x-4x+x^2+3] = 3x^2 - [x^2+3x+3] = 3x^2-x^2-3x-3 = 2x^2-3x-3 You can see this at this url: http://www.wolframalpha.com/input/?i=3x^2+%E2%80%93+[7x-+%284x+%E2%80%93+x^2%29...
*June 10, 2016*

**Physical Science**

That would depend on the applied force. F = ma You can take it from there.
*June 10, 2016*

**O98 algebra**

The sum of her first 5 scores is 382 6*77 = 462 6*85 = 510 So the last score must satisfy 462 < 382+x < 510 80 < x < 128 So, any score above 80 will get her a C grade.
*June 10, 2016*

**Math: Inverse Function (Plz help)**

f = 8+√(8+x) to find f^-1, swap variables and solve for f: x = 8+√(8+f) x-8 = √(8+f) x^2-16x+64 = 8+f f = x^2-16x+56
*June 9, 2016*

**analytical math**

no idea. How old is Mary now?
*June 9, 2016*

**Math**

42
*June 9, 2016*

**Math**

.20 * 20 = 4
*June 9, 2016*

**Pre-Cal: Domain (cont.)**

#8 the domain is all real numbers except 0 and -7 While the domain of [5(x+7)]/[7x] excludes only 0, (f/g)(x) requires evaluating both f and g, and since g(-7) is not defined, neither is (f/g)(-7)
*June 9, 2016*

**Math**

just keep adding 11
*June 9, 2016*

**Algebra**

or, since you are given a point and a slope, try using the point-slope form of the line: y-11 = (7/3)(x-3) That's good enough for me. What you want depends on what you mean by "the equation" of a line.
*June 9, 2016*

**math**

the surface consists of three pairs of rectangular faces. You have the length and width of each face, so find the three areas, add 'em up, and double that (since there are two of each size)
*June 9, 2016*

**algebra 2B**

I suspect a typo g(x) =− 2 −x 2+ 4 is the same as -2 - x^2 + 4 = 2-x^2 Clean it up and show how far you got.
*June 9, 2016*

**algebra**

y = (2x-3)/(7x+1) see http://www.wolframalpha.com/input/?i=%282x-3%29%2F%287x%2B1%29
*June 9, 2016*

**Math**

if you want the height, drop the altitude to the base. It divides the base into two parts, x and 12-x. Now, using the Pythagorean Theorem, you can find the height h using x^2 + h^2 = 8^2 (12-x)^2 + h^2 = 7^2 subtract and you get rid of h, leaving x^2 - (12-x)^2 = 64-49 24x - ...
*June 9, 2016*

**Physics- Help!!**

120 * (1200/100) = ?
*June 9, 2016*

**math**

do you see what a useless response that is? Restrict how? Anyway, I gave you the information you need. How about showing some effort of your own here?
*June 9, 2016*

**math**

infinitely many. Or did you want to restrict the available area? In the first quadrant, (4,4) is on the curve. There will be none to the left of (1,16) or to the right of (16,1). And don't count the lattice points on the curve...
*June 9, 2016*

**Pre-Cal: Domain**

the domains include all real numbers except where the denominator is zero. So, figure the resultant function, and then exclude any places where the denominator is zero. AND, exclude 0 and -7 because at those values f or g is undefined, so even though some mixture of them might...
*June 9, 2016*

**Calculus**

you are correct. 1/(x-1) -> ∞ I tried to pound a round peg into a square hole.
*June 9, 2016*

**Calculus**

note that if u = 1/(x-1) then what you have is sin(u)/u You have probably seen that this limit is 1, so follow the same argument. Or, try google. A good discussion is at math.ucsb.edu/~jcs/SqueezeTheorem.pdf
*June 9, 2016*

**Math/Dosage Calculations**

just add up the amounts (in fl oz): (1/3)(8) + (1/2)(16) + 3 = 41/3 fl oz. Now just convert that to mL. 1 oz = 29.57 mL Hmmm. I get 404 mL
*June 9, 2016*

**Math**

Just take each sentence and place the required digit in for one of the x's. Start with xxxx My hundreds digit is the last odd number. x9xx and move right along.
*June 9, 2016*

**Math**

w*2w = 1250 Now get w, then the length is 2w
*June 9, 2016*

**Math**

that would be the area of the inner cylinder, plus the area of the outer cylinder, plus the area of the two rings at the end. So, if R = outer radius r = inner radius h = length of pipe the total area is 2πrh + 2πRh + π(R^2-r^2) = 2πh(r+R) + π(R+r)(R-r...
*June 9, 2016*

**Math - Year 10 - Simult. Equations**

just plug in y=3x and you get x^2 + (3x)^2 = 10 Now x is easy, and then y=3x.
*June 9, 2016*

**geography**

how many time zones in between? That's the number of hours. Or, if you know the longitudes, since there are 24 hours in a 360° circle, each hour covers about 15°
*June 9, 2016*

**geometry**

since j is in the middle, mn = mj+jn = 6 3/4 + 6 3/4 = ?
*June 9, 2016*

**trigonometry**

If that fails, try cot (x-y)/2 and use your half-angle formula, and more parentheses next time.
*June 8, 2016*

**math**

sure, if so designated
*June 8, 2016*

**Math**

even without calculus, you can do these. Just think of what you know about lines and parabolas. Then you can verify your Algebra I with calculus. What do you think?
*June 8, 2016*

**math(bearing)**

There seems to be a lot of noise here If the bearing of Y from Z is 280, then the bearing of Z from Y is 280-180 = 100
*June 8, 2016*

**Pre-Cal (Help Plz)**

come on. x^2-4 is negative on the interval (-2,2) So, since |x^2-4| is always positive, that little arc below the x-axis is flipped up above it. Everywhere else, the two functions are identical. g(x) = -f(x) if |x| < 2 g(x) = f(x) if |x| >= 2
*June 8, 2016*

**Pre-Cal (Help Plz)**

take a look at the graphs and see what you can say. And why not use || for absolute value? It's not like you don't have the characters... http://www.wolframalpha.com/input/?i=plot+y%3Dx^2-4,+y%3D|x^2-4|
*June 8, 2016*

**math**

ok
*June 8, 2016*

**Trigonometry**

off course as measured how? Actual distance between target and position, or distance perpendicular to the intended course? In the first case, use the law of cosines. Both sides of the included angle are 152*2
*June 8, 2016*

**Trigonometry**

draw the diagram. It should be clear that if the height is h, h cot32° - h cot40° = 12
*June 8, 2016*

**Trigonometry**

draw the diagram. It should be clear that north: 83 cos37° west: 83 sin37°
*June 8, 2016*

**math**

looks good to me.
*June 8, 2016*

**Math - eh?**

NO IDEA! Where the heck is X?
*June 8, 2016*

**PreAlgebra**

x^2 = 22^2 - 7^2 now just crank it out
*June 8, 2016*

**Math**

your formula is correct, but your answer is not. Oh, well.
*June 8, 2016*

**Math**

a = 2πr(r+h) = 2π(9)(9 + 19) = 504π So, D How did you get 523?
*June 8, 2016*

**Math**

yes, it is correct.
*June 8, 2016*

**Science**

PV/T is constant, so you want T such that 1.82*18.7/353 = 1.41*25.1/T T ≈ 367
*June 8, 2016*

**aptitude**

clearing fractions and decimals, we have 125x + 5y = 21 3x + y = 3 now you can substitute y = 3-3x to get 125x + 5(3-3x) = 21 Now it's easy to solve for x, and then you can get y.
*June 8, 2016*

**Algebra**

Seems we want cube roots: ∛540r^3 s^2 t^9 = ∛27*20 r^3 s^2 (t^3)^3 = 3rt^3 ∛20s^2 so, yes, you are correct
*June 8, 2016*

**maths**

just plug in values for t: x(2) = 16*2 - 2*2^2 = 32-8 = 24 likewise for t=6
*June 8, 2016*

**math**

starting with 1, after chocolates, 3/5 remains after gift to sister, she has 8/9 * 3/5 = 8/15 after books, she has 1/4 * 8/15 = 2/15
*June 8, 2016*

**Math**

so, which ones did you get? Show some work, eh? This is a massive homework dump. And sorry, you will have to describe the graphics is possible.
*June 8, 2016*

**Trigonometry**

as usual, with fractions, cross-multiply, and you will see one of your standard identities.
*June 8, 2016*

**Trigonometry**

I assume you mean 4sin^2(3θ) - 3 = 0 sin^2(3θ) = 3/4 sin(3θ) = √3/2 3θ = 60° or 120° θ = 20° or 40° Since sin(3θ) has period 360/3 = 120°, add multiples of 120° to those values. You will find six solutions in the ...
*June 7, 2016*

**Trigonometry**

you have tanx = -2 so, the solutions will be in QII and QIV.
*June 7, 2016*

**Trigonometry**

since sin^2x = 1 - cos^2x, make that substitution, and then solve the quadratic for cos(x)
*June 7, 2016*

**Trigonometry**

No idea what a double identity is, but draw the triangle. The missing side is √24. In QII, that means x is negative, so cosθ = x/r = -√24/5 cotθ = x/y = -√24/1
*June 7, 2016*

**math**

clearly the major axis has length 13, and the minor axis has length 12. So a = 13/2 b = 6 c^2 = a^2-b^2 = 25/4, so c = 5/2 The center is at (13/2,0), so h = 13/2 and k=0 The foci are at (h±c,k) Since the major axis is horizontal, that means the equation is (x-h)^2/a^2...
*June 7, 2016*

**Math**

so, no, A is not correct.
*June 7, 2016*

**math**

a = 0.9 o so, o = a/0.9 = 1.111a so, the orange is 11% heavier than the apple. The grapefruit is just noise.
*June 7, 2016*

**math**

do you even look at what you type? That's "sides" not "size"! and "menion" just escapes me totally! If the two diagonals are x and y, then using the law of cosines, and the fact that consecutive angles are supplementary, x^2 = 6^2+9^2 - 2*6*9 ...
*June 7, 2016*

**Algebra**

It sounds like you want a recursive sequence, where T(n+1) = 4Tn - Tn^2 If so, then if Tn = 4*2.4 - 2.4^2 = 3.84 T(n+1) = 4*3.84 - 3.84^2 = 0.61
*June 7, 2016*

**math**

5000*1.01^8 + 10000*1.01^16
*June 7, 2016*

**Math Help Please**

Note which side is opposite to A and adjacent to A. Now review your basic trig functions. You can see that sinA = BC/AB cosA = AC/AB so you are correct. Extra credit: How did I figure it out, with no triangle to refer to?
*June 7, 2016*

**value**

you don't move on a bearing. You move on a heading. You observe on a bearing. Starting from R at (0,0), P moves to (-20/√2,-20/√2) Q moves to (15√3/2,15/2) now just find the distance between those points. Or, use the law of cosines. The angle between ...
*June 7, 2016*

**algebra**

12 mg / kg * 1kg/2.2lb * 120lb = 655mg
*June 7, 2016*

**maths**

What do you mean when you say when it is perpendicular to it ?? when what is perpendicular to what?
*June 7, 2016*

**Maths**

1+1 = 2 You have some other questions?
*June 7, 2016*

**Maths**

DBA = BDC = 28° DBC = 90° - DBA = 62°
*June 7, 2016*

**Math (money)**

(x - 200)(.80) - 131 = .20x x = 485 check: start: 485 dress: 200 leaves 285 bag: 57 leaves 228 shoes: 131 leaves 97 = 20% of 485
*June 7, 2016*

**MATH - ??**

Ouch! I got confused on the period/comma usage disparity. Or, I could just say I was figuring in km instead of meters!
*June 7, 2016*