Thursday

August 25, 2016
Total # Posts: 42,774

**Algebra**

count the tickets: g+s = 215 count the dollars: 10g+6s = 1990 Now crank it out.
*July 7, 2016*

**Geometry**

rewrite as y = 2x-3 and you can read off the slope and intercept
*July 7, 2016*

**Pre-Cal**

oops sinx = 8/17 so, cosx = 15/17 sin2x = 2 sinx cosx = 2 * 8/17 * 15/17 = 240/289
*July 7, 2016*

**Pre-Cal**

sinx = 8/17 so, cosx = 15/7 sin2x = 2 sinx cosx = 2 * 8/7 * 15/7 = 240/49 do the others similarly.
*July 7, 2016*

**Algebra**

Huh? It's already written out. That's how I got the equation. Can you not solve the equation? If you find x, that's how many lbs of worms you need. The rest (30-x) is bears.
*July 7, 2016*

**Algebra**

If x lbs of worms, then 7x + 3(30-x) = 4.60*30 This is just like the interest problem, which is also a mixture problem.
*July 7, 2016*

**Pre-Cal**

recall that tan(x-y) = (tanx-tany)/(1 + tanx tany)
*July 7, 2016*

**Algebra**

If $x is at 8%, then .08x + .09(10000-x) = 860
*July 7, 2016*

**Physics - tense**

I'm waiting for the answer here... Talk about tension!
*July 7, 2016*

**Maths**

Yeah, I noticed that. I can't figure why the closest answer is so far off. To get 12.2 years, r needs to be 9.58%
*July 7, 2016*

**geometry**

review your basic trig functions, and from a distance of x feet, 1149/x = tan 89° Now just solve for x.
*July 7, 2016*

**Calculus**

recall that the range of an object is R = v^2/g sin2θ so, figure some pairs of value that make that 100 miles. Of course, that formula implies a flat earth, and 100 miles is far enough away that varying gravity and earth's curvature require some modifications.
*July 7, 2016*

**Maths**

For n sides, there are n-2 straight angles, or 2(n-2) right angles. So, n=17
*July 7, 2016*

**MATH Function Transformation**

If you mean a polynomial such as a(x-p)(x-q)(x-r)... then a is the vertical scale value, so a = 1/2 means the y values are half as big: a compression ratio. stretching and compression are just two ways of looking at a scale factor. Usually a compression means a < 1 and a ...
*July 7, 2016*

**Math**

75 min = 1.25 hours, so 15.4mi/1.25hr = 12.32 mi/hr
*July 7, 2016*

**math**

that is one way. The other way is to use the Remainder Theorem and evaluate f(1). That is the remainder R.
*July 7, 2016*

**Math Please Help**

you just want d(t) > -16 t^3-9t^2+6t > -16 t^3-9t^2+6t + 16 > 0 (t+1)(t-2)(t-8) > 0 Now, using what you know about the general shape of cubics, you know that this one will come up from the lower left, then cross the t-axis at -1,2,8. Since it started out negative, ...
*July 7, 2016*

**math**

review your basic trig functions: h/450 = tan 20°
*July 7, 2016*

**algebra2**

If there are x cows and y chickens, you know (counting heads) x+y = 35 Now, counting legs, you know: ??? Work that out, then solve the two equations.
*July 7, 2016*

**AB Calculus**

Assuming all logs are base b (since the base does not matter for this kind of stuff), we have (I think) log ∜(x^7 y^2 / z^4) = 1/4 log(x^7 y^2 / z^4) = 1/4 (7logx + 2logy - 4logz) = 7/4 logx + 1/2 logy - logz or, (b)
*July 7, 2016*

**math**

Since y has an absolute maximum, it must be of even degree, since all the odd-degree polynomials go forever in each direction. And, its leading coefficient must be negative, since the graph opens downward.
*July 7, 2016*

**Maths**

Since multiplying logs is not one of the usual operations, and none of the answers includes (x-6) I'd say you are in trouble from the start. I suspect that you were given -2logb^x -6logb^y + 1/7 logb^z That is choice (a), assuming the usual sloppiness with notation.
*July 7, 2016*

**math**

A little synthetic division shows that the remainders are -9m-92 and 23-4m If they are equal, then m=-23 P(-3) = P(2) = 115
*July 7, 2016*

**Advanced Function**

the volume increases by the cube of the linear scale. So, he needs a scale factor of no more than ∛9 = 2.08
*July 7, 2016*

**geometry**

well, you know that m∠ABE is half of the total, since BE bisects ∠ABD.
*July 7, 2016*

**Maths**

What's to figure out? They gave you the exact formula you need. 9% growth means it grows by a factor of 1.09 each year, so t = ln3/ln1.09 = ?
*July 7, 2016*

**General Mathematics**

8 + 1.5*ceil(x) for x km above 4. where ceil(x) (ceiling function) is the least integer greater than or equal to x.
*July 7, 2016*

**Algebra**

110*55 = ?
*July 7, 2016*

**Science**

30√2 SW is the same as 30S and 30W So, now add up all your distances and see where you end up. The answer will be surprisingly easy.
*July 7, 2016*

**geometry**

(B+b)/2 * h fill in the values
*July 7, 2016*

**math**

Not always. Never for rectangles.
*July 7, 2016*

**AHOOGAAH! Homework Dump**

No ideas on any of these?
*July 7, 2016*

**Math**

(3 + (2/3)(-3-3),(2 + (2/3)(5-2)) = (3-4,2+2) = (-1,4)
*July 7, 2016*

**Math**

well the slope of the line between (-2, -1) and (6, 8) is (-1-8)/(-2-6) = 9/8 now use the point-slope form of the line
*July 7, 2016*

**Calculus**

Let u = tan(π/4 sin(2x)) du = sec^2(π/4 sin(2x))*(π/4)(2cos(2x)) du So, what you have is just ∫du with some constant factored out.
*July 7, 2016*

**General Math**

since pure juice is 100% juice, add up the amounts of juice: .50(6) + 1.00(x) = .75(6+x)
*July 7, 2016*

**physics PS**

Oops -- v = 2/3 t^3 i + 2/3 t^2 j
*July 7, 2016*

**kashinath palod**

FF = ma = 6t^2i + 4tj Since m=3, a = 2t^2i + 4/3 t j so, v = 2/3 t^2 i + 2/3 t^2 j
*July 7, 2016*

**Calculus**

well, sin^2(x) = 1/2 (1-cos(2x)) that should be easy to integrate, right?
*July 7, 2016*

**maths**

I have never heard of the word kharch, but the apple's share is 5/(6+10+5) = 5/21
*July 7, 2016*

**math**

well, ADB is also an isosceles right triangle with sides of 5. So, its hypotenuse is AB = 5√2 that help?
*July 7, 2016*

**Math**

Well, the 1st term in the rth group is 1,2,4,7,11,... = 1+ 0,1,3,6,10 = 1+ r(r-1)/2 That should get you started.
*July 7, 2016*

**Math**

looks good
*July 7, 2016*

**pre cal**

6(x^2 - 2/3 x + 1/9) = 6(x - 1/3)^2
*July 7, 2016*

**Pre-Cal**

(csc θ − sin θ)/(cos θ) = (1/sinθ - sinθ)/cosθ = (1-sin^2θ)/(sinθ cosθ) = cos^2θ/(sinθ cosθ) = cosθ/sinθ = cotθ
*July 6, 2016*

**Pre-Cal**

(sin^2 + cos^2)/cos = 1/cos
*July 6, 2016*

**java program**

letter = (n>=90) ? "A" : (n>=80) ? "B" : (n>=70) ? "C" : (n>=60) ? "D" : "E";
*July 6, 2016*

**Algebra**

check the slopes. If their product is -1, the lines are perpendicular. That is, if one slope is the negative reciprocal of the other.
*July 6, 2016*

**Math**

Thunk of it using actual numbers. If he can mow the lawn in 4 hours, how much in 2 hours? 2/4 So, it will take him 2/x hours. If it takes him x hours, he does 1/x of the job in 1 hour. So, twice that, or 2/x in 2 hours.
*July 6, 2016*

**math**

ever hear of actual math symbols? 3√5 - 2√7 + √245 - √28 3√5 - 2√7 + √(49*5) - √(4*7) 3√5 - 2√7 + 7√5 - 2√7 10√5 - 4√7
*July 6, 2016*

**MATH HELP**

In 30 minutes, the first bus has gone 39 miles The 2nd bus goes 15 mi/hr faster. So, how long does it take to cover the extra 30 miles? It's the same as if the 1st bus stopped 30 miles away, and the 2nd bus drove 15mph to meet it.
*July 6, 2016*

**Chemistry**

sure looks like D to me twice the value, opposite direction
*July 6, 2016*

**math**

what, you cannot add 600+3200 ?
*July 6, 2016*

**Normal Distribution**

you can play around with Z table stuff at http://davidmlane.com/hyperstat/z_table.html
*July 6, 2016*

**math**

not sure what the scaling has to do with anything, as the scaled polygon is never mentioned. However, it should be easy to convince yourself that such a scaling does not change any of the slopes or angles involved.
*July 6, 2016*

**Math**

yes, it can. Because to be even f(-x) = f(x) This is true only (and always) if all the exponents are even.
*July 6, 2016*

**Math**

the highest exponent is the degree the order of a root is the number of times it appears. So, you have three roots of degree 1. Any polynomial of degree n has exactly n roots, though all may not be unique (order 1).
*July 6, 2016*

**algebra 2-1**

x=42
*July 6, 2016*

**Pre Calculus**

again, only one possible choice, since e^1 = 2.718 e^2 = 7.389 e^3 > 16
*July 6, 2016*

**Pre Calculus**

x = 5/2 Now if you mean 2^x = 5 The answer should be clear, since 2^1 = 2 2^2 = 4 2^3 = 8
*July 6, 2016*

**Math**

since time * speed = distance, and the two distances are the same, 60t = 70t + 3/2 find t, then use that to get the distance
*July 6, 2016*

**maths**

make that 100° (130-30)
*July 6, 2016*

**maths**

use the law of cosines: QR^2 = PQ^2 + PR^2 - 2 PQ PR cos 130
*July 6, 2016*

**Math - eh?**

between 20,000 and 40,000 2xxxx 3xxxx 4xxxx mumble mumble My hundred digit is the sum of my ten thousands digit. ???
*July 6, 2016*

**math**

The minute hand has advanced 25/60 = 5/12 of a circle, or 150° The hour hand at 6:00 is at 180°, and it has advanced 5/12 of the way to the 7, or 5/12 * 30 = 12.5° So, the angle is 12.5+30 = 42.5°
*July 6, 2016*

**math**

no drawing here
*July 6, 2016*

**math**

at what time?
*July 6, 2016*

**Math (Analytic Geometry)**

Assuming you just want verification of your results, 1. y + 5/2 = 6/5 x 2. (x+8)^2+(y-8)^2 = 4((x+2)^2+(y-2)^2) or, x^2+y^2 = 32 3. Clearly this is the ellipse with foci at the two points, and a=6, c=4, b^2=20 x^2/36 + y^2/20 = 1 see http://www.wolframalpha.com/input/?i=...
*July 6, 2016*

**See a Therapist**

You clearly have a split personality and can't even tell that you keep posting the same problems again and again.
*July 6, 2016*

**Analytic geometry**

they lie on the perpendicular bisector of the line between the two points. That line has slope -5/6, so its perpendicular has slope 6/5 The midpoint of the line segment is (0,-5/2), so the line you want is y + 5/2 = 6/5 (x-0)
*July 6, 2016*

**MATH**

you need to cut off a slice 2√5 wide.
*July 6, 2016*

**arithmetic sequence**

A9 = A1 + 8d
*July 6, 2016*

**arithmetic sequence**

there are 4 terms past the first, so divide 92/4 to get the difference between terms
*July 6, 2016*

**arithmetic**

10000
*July 6, 2016*

**math**

what are the factors of 65? 5 and 13 looks like they work
*July 6, 2016*

**Math**

a+2d = 8 a+8d = 3*8+2 so, a=2 and d=3 Now you want S19 = 19/2 (2*2 + 18*3)
*July 6, 2016*

**Meths**

since distance = speed * time, 60t + 11/2 = 70t Now you have the time it takes, so you can find the distance.
*July 6, 2016*

**Math**

vertical asymptotes: y = 1/((x+6)(x-7)) y(6) = 0, so y = (x-6)/((x+6)(x-7)) horizontal asymptote at y = 10/9 needs a quadratic on top, so we could have y = (10/9)(x-6)^2/((x+6)(x-7)) but that does not really cross the x-axis at x=6, but just touches it. So, how do we get that ...
*July 6, 2016*

**Phisics**

measured in Joules. So, look up the definition of a Joule.
*July 5, 2016*

**chem 121**

just plug in your formula PV = nRT n = PV/RT n is the number of moles. Now multiply by A, Avogadro's constant to get the number of molecules. Or, since R = kA, n = PV/kAT so nA = PV/kT gives the number of molecules
*July 5, 2016*

**math-steve**

Hmmm. I drew a tree with all possible outcomes, but I forgot to weight each branch with its probability. Try doing that and see what happens. I'll try to get back later.
*July 5, 2016*

**Science**

at time t, s = 20t + 1/2 a t^2 so, we can find a by solving 20*30 + 1/2 a * 30^2 = 1200 a = 4/3 m/s^2 v = 20 + at = 20 + 4/3 * 30 = 60 m/s
*July 5, 2016*

**Math**

I'll assume that s is the length of a side. After the borders are discarded, an (s-2)x(s-2) square remains. There are 2(s-2)-1 = 2s-5 squares on the diagonal, so the remaining squares number (s-2)^2 - (2s-5) = s^2-6s+9 = (s-3)^2 you can easily check this for small s.
*July 5, 2016*

**Pre Calculus**

Since log(xy) = log(x) + log(y) regardless of the base, and considering the chance of typos, I'd go with (e)
*July 5, 2016*

**science**

sets of vectors? 10,20,30 are just three scalars. Try again.
*July 5, 2016*

**Math**

well, 15 1/2 = 15.5 So I'd guess 2.155 but that's certainly an unusual way to express a value. In fact, I'd guess it's a typo. I've never seen a mixture of decimal and fraction like that.
*July 5, 2016*

**Maths**

use your sum-to-product formulas: cosB-cosA = 2 sin (A+B)/2 sin (A-B)/2 cosA+cosB = 2 cos (A+B)/2 cos (A-B)/2 now just divide
*July 5, 2016*

**math**

1/10 to end up with exactly 27 6/10 to end up with at least 27 4/10 to lose
*July 5, 2016*

**math**

22+25-2
*July 5, 2016*

**Pre-Calculus 11**

2∛3 + 5∛3/4 = ∛3 (2+5/4) = ∛3 (13/4) or maybe 2∛3 + 5∛(3/4) = (5+2∛4)∛(3/4) = 1/2 ∛3 (4+5∛2) -12√11 + 5√11 = -7√11 Other than that I don't see much joy
*July 4, 2016*

**math**

875 * (1+2)
*July 4, 2016*

**Math of investigation**

Hmmm. I originally rejected the idea that the centers would lie on the diagonal, because I thought the circles would overlap or not fill the maximum area. I'm not sure how your equation comes about, but it appears you have solved the problem.
*July 4, 2016*

**Object Oreinted Programming in java**

not much object usage there. Just about a dozen lines of code, mostly I/O.
*July 4, 2016*

**Economics/Finance**

You don't say what he started with. Assuming $2000, at the end of year 2 he has 2000*1.05^2 at the end of year 4, he has 2000*1.05^4 + 2000*1.05^2 so, after 20 years, that's 10 investments, totaling 2000 (1.05^20 + 1.05^18 + ... + 1.05^2) Now, 1.05^2 = 1.1025 so that&#...
*July 4, 2016*

**Pre Calculus @Reiny**

Good job with the formatting!! Did you post somewhere in the past as a scratchpad?
*July 4, 2016*

**Pre Calculus**

A little synthetic division shows that f(x) = (x-(6+√6))(x^2+(√6-5)x+(√6-6))+2 I leave it to you to verify that f(6+√6) = 2
*July 4, 2016*

**Math**

a = πrs where 2πr = 132 s^2 = r^2+h^2
*July 4, 2016*

**geometry**

Draw a diagram. If the hat's radius is r, then r^2+r^2 = 15^2 and the diameter is just 2r
*July 4, 2016*

**Math**

just multiply the volume of metal by its density to get the mass: cm^2 * g/cm^3 = g You know that the volume of a sphere of radius r is v = 4/3 πr^3 so, to get the volume of metal, just subtract the volume of the empty inner sphere from the outer sphere.
*July 4, 2016*

**Math**

the mean of 2,3,5 is 10/3 So, to have a mean height of 30, each number must be multiplied by 9, giving heights in the ratios 18:27:45 If 4 plants have a mean of 33, their sum is 4*33 = 132 18+27+45=90, so the 4th plant has height 42
*July 4, 2016*