Saturday

August 27, 2016
Total # Posts: 42,817

**math**

since ln2 < 1 1/ln2 > 1 so it diverges
*July 31, 2016*

**Math**

width:length = 600:800 = 6:8 = 3:4 study up on reducing fractions. You divide out the common factors, top and bottom.
*July 31, 2016*

**Math**

see previous post
*July 31, 2016*

**math**

of course not. List a few terms.
*July 31, 2016*

**MATH**

a simple convergent geometric series is r^n where r<1. (1/n - 1/n^2) = (n-1)/n^2 < 1 for all n>0 In fact, 1/n (1 - 1/n) < 1/n < 1/2 for n>2. So, An < 1/2^n for n>2
*July 31, 2016*

**Need Help Please- Pre-Calc**

the period of sin(x) is 2π. the period of sin(-π/3 x) is 2π/(π/3) = 6 You need to multiply by the amplitude. You need to reflect in the x-axis, since sin(-x) = -sin(x) so, the quarter points are (0,0), (3/2,-5), (3,0), (9/2,5), (6,0) see the graph at http...
*July 31, 2016*

**Mathis**

don't ask much, do you? n=0 sum=0 while n<100 n += 2 sum += n end while print sum
*July 31, 2016*

**Maths**

4logx+6logx-7logx=log27 log x^4 + log x^6 - log x^7 = log 27 log (x^4*x^6/x^7) = log 27 ... see what you can make of that
*July 31, 2016*

**math (integral)**

maybe not bogus, but not elementary either: https://en.wikipedia.org/wiki/Gaussian_integral
*July 31, 2016*

**Math**

0 and 9 -34 and -43 -34 and -25 1000001 and 1000010 I think you get the picture
*July 31, 2016*

**algebra**

the original fraction is x/(x+2) (x-1)/(x+2-1) = 1/2 now just solve for x.
*July 31, 2016*

**Kalafaanschool**

tends to slow down
*July 31, 2016*

**Maths**

24 * 1/2 * pi/6 * 6^3 cm^3
*July 31, 2016*

**GENERAL MATHEMATICS**

sec = 1/15 asst = 1/32 (32+x)/(2x+15) = 7/6 2(x + 1/x) = 33/16 and so on. See what you can do with the others here, as well as your two later posts. Do not expect someone here to do your whole assignment. You must be able to make some headway on at least some of them, no?
*July 31, 2016*

**Geometry**

follow the hint, and place P 3/7 of the way from A to B.
*July 31, 2016*

**rawani**

you can consider one of the forces along the x-axis. Let's use the 10N one. Then the two forces are <10,0> and <6.93,4.0> Add hem up to get <16.93,4.0> or 17.40N at an angle of 13.3° from the 10N force.
*July 31, 2016*

**MATH**

The terms of the sequence are (3/4)^n * n^10 or, n^10 / (4/3)^n I'm sure you've seen proofs that exponentials grow faster than polynomials, so this limit --> 0 a google search will turn up many proofs of this, such as http://math.stackexchange.com/questions/55468/...
*July 31, 2016*

**MATH**

Take a look at the first few terms in the series: 2/4 - 2/6 2/5 - 2/7 2/6 - 2/8 2/7 - 2/9 ... You can see that the terms start to cancel out. Taking the infinite sum, they all vanish except 1/4 + 2/5 = 9/10
*July 31, 2016*

**MATH**

Since (-1)^n / n converges, so does this one. n^3/(n^4+1) < 1/n
*July 31, 2016*

**math**

that will be an equilateral triangle of side 6.
*July 30, 2016*

**Physics**

The excellent article on wikipedia https://en.wikipedia.org/wiki/Trajectory discusses finding the maximum range on a slope. You can use that to solve for the problem's conditions.
*July 30, 2016*

**Math**

figure its fuel consumption rate, in gallons/hr * 4 multiply that by the weight per gallon.
*July 30, 2016*

**Science**

depends on the distance of the fulcrum.
*July 30, 2016*

**Calculus**

Using the ratio test, An+1/An = (n+1)!/(n+1)^(n+1) --------------------- x n!/n^n = (n+1)!/n! n^n/(n+1)^(n+1) x = (n+1) (n/(n+1))^n * 1/(n+1) x = (n/(n+1))^n x Hmmm. what to do? = ((n+1)/n)^-n x = (1 + 1/n)^-n x This should look ...
*July 30, 2016*

**matg**

first step is usually to get rid of the nasty fractions. I see there's a typo in the first equation. I'll just assume 9/4 x. If wrong, fix it and follow the same steps to solution. 18x + 3y = -18 -4x + 45y = 4 or 6x + y = -6 -4x + 45y = 4 multiply to get rid of x: 12x...
*July 30, 2016*

**AHOOGAAH! Homework Dump**

no ideas on any of these?
*July 30, 2016*

**Calculus AB**

did you do the sketch? It should be clear that l/5.5 = (x+l)/12 no crank it out. Algebra I, babe.
*July 30, 2016*

**Calculus AB**

see similar previous problem. Just express r as a function of h and plug it in.
*July 30, 2016*

**Geometri euclid**

If the two circles have radii r and R, then the area between the circles is π(R^2-r^2) If a circle has AB as a diameter, then BC is its radius, since AB = AC + BC BC^2 + r^2 = R^2 so, BC^2 = R^2-r^2 That means the area of the circle with BC as its radius (AB as its ...
*July 30, 2016*

**Calculus AB**

v = 1/3 pi r^2 h But the dimension of the tank indicate that at any time, r/h = 4/10 So, use that to eliminate r.
*July 30, 2016*

**Calculus AB**

You know where the roots are. You know that if the root is of odd order, the graph crosses the x-axis there. And, if the root is of even order, the graph is just tangent there. So, knowing what you do about the general shape of polynomials, since this one is of even order, The...
*July 30, 2016*

**Math**

ratio test says no
*July 30, 2016*

**Math**

the two graphs are x^2 + y^2 = 1 (x-2)^2 + (y-3)^2 = 16 x^2-4x+4 + y^2-6y+9 = 16 but, x^2+y^2 = 1, so that means -4x+4 + 1 -6y+9 = 16 4x+6y = -2 so the slope of the line is -2/3 No need to actually find the points.
*July 30, 2016*

**Math**

Oops. Not all of those are on the graph. You may be right.
*July 30, 2016*

**Math**

well, let's see n x y 23 94 -98 22 90 -95 ... -22 -86 37 -23 -90 40 -24 -94 43 -25 -98 46 Looks like a lot more than 9 to me.
*July 30, 2016*

**Math**

eliminate t: (30-x)/40 = (50+y)/30 30(30-x) = 40(50+y) 900-30x = 2000+40y 30x+40y = -1100 3x+4y = -110 x = 4n+2 y = -(3n+29) Now just work out how many values of n produce x and y in the desired interval.
*July 30, 2016*

**Physics**

google is your friend. Use it.
*July 30, 2016*

**math**

See joejoe's post below. Same problem, different letters.
*July 30, 2016*

**Trigonometry**

Just factor out sinx: sinx(6sinx-1) = 0 so, sinx = 0 or sinx = 1/6 each will provide two solutions.
*July 30, 2016*

**Trigonometry**

The ship turned 90 degrees. So, the distance from port is just the hypotenuse of a right triangle with legs 7 and 24. Look familiar?
*July 30, 2016*

**math**

Assuming you mean the ratio of areas, If BC = 2x, then AD = 2x ABD has area 1/2 * 2x * 2x = 2x^2 ABEF has area (2x)*(2x) = 4x^2
*July 30, 2016*

**Math**

Sn = a(1-r^n)/(1-r) so, S5 = a(1-r^5)/(1-r)
*July 30, 2016*

**Algebra**

Col. Mustard, of course!
*July 30, 2016*

**Math**

In the interval -pi/4 <= t <= pi/4, the graph is traced once. But on 0 <= t <= pi/2, only half the curve is completed. Try changing the domain on this plot at http://www.wolframalpha.com/input/?i=plot+x%3Dcos(4t),y%3Dsin(6t),+-pi%2F4+%3C%3D+t+%3C%3D+pi%2F4
*July 30, 2016*

**math**

it's not that b is the middle value, but that if we want to build a set of ratios, a:b:c we need to have a common value for b in the two ratios a:b and b:c We could not have placed a or c in the center spot, because we only had one ratio for each of those. But to join the ...
*July 29, 2016*

**math**

a:b = 2:3 c:b = 3:2 we want b in the middle, so b:c = 2:3 lcm(2,3) = 6, so now we can write a:b = 4:6 b:c = 6:9 a:b:c = 4:6:9 a:c = 4:9
*July 29, 2016*

**Calculus**

try using the ratio test. You should be able to show that the series converges for |x| < e
*July 29, 2016*

**Calculus AB**

well, you want cos x = -0.4 so, x will be an angle in QII or QIII Your reference angle is arccos(0.4) = 66.4° so, x will be 180±66.4°
*July 29, 2016*

**math**

looks good to me Make sure you specify mm^3 for volume. That's a dang small prism, to be sure...
*July 29, 2016*

**math**

A(1+.12*5) = 160000
*July 29, 2016*

**Calculus AB**

it's an even multiple of 2pi, so the functions are the same as for 0.
*July 29, 2016*

**Calculus AB**

recall that log_a(b) = ln(a)/ln(b) So, converting everything to natural logs (or any set of logs with a common base), ln3/ln25 x + ln7/ln2 y = ln27/ln5 ln8/ln7 x + ln5/ln3 y = ln2/ln49 Now just solve the system as usual. It's messy, but it's just numbers. If you don&#...
*July 29, 2016*

**statitics**

just list the cases: P(WL) = 0.60*0.25 P(LW) = 0.40*0.55 Since they are mutually exclusive, P(WL)+P(LW) = 0.37
*July 29, 2016*

**math**

Divide 32 by the number of colors. Then count over in the list the remainder. For example, your list has 5 colors 32/5 = 6 R2 So, there are six complete cycles, with 2 left over. The 32nd stripe is thus blue. If you only wanted 4 colors, the do that division instead. A zero ...
*July 29, 2016*

**luderitz**

not following instructions, as in the subject of your post.
*July 29, 2016*

**Math**

.85x +.60*150 = .80(150+x)
*July 29, 2016*

**math**

x = (90-x)-8
*July 29, 2016*

**Math**

35 m/s * 1km/1000m * 3600s/hr = ? km/hr
*July 29, 2016*

**science**

If the distance is x meters, then since time = distance/speed, x/55 + x/330 = 7 x = 330m Now, the problem is that the bullet will drop 176m in the 6 seconds spent in the air. So, now we have to include the angle of the trajectory, which complicates matters some.
*July 29, 2016*

**Maths**

Review your sine rule. It is then clear that sinθ = √(15^2-6^2)/15 It might have been easier to calculate using cosθ = 6/15
*July 29, 2016*

**Accounts**

2000(1+.06/2)^(2*6)
*July 29, 2016*

**Stats**

Your Z table tells you that about 97% of the population lies below the mean + 1.88 std. so, ...
*July 29, 2016*

**Physics**

If I can get by the sloppy typing, it is clear that h^2 + 2^2 = 9^2
*July 29, 2016*

**math**

the number who passed either or both is .80+.85-.75 = 0.90 So, 10% of x students failed both: 45 = 0.10x . . .
*July 29, 2016*

**PACE INter Science Colldege**

100km/hr * 1L/10km * 1hr/3600s * 1000cm^3/L = 27.77 cm^3/s
*July 29, 2016*

**Math**

the linear ratio is √25:64 = 5:8 the volume ratio is thus 5^3:8^3 = 125:512 or, 250:1024
*July 28, 2016*

**math**

If the dimensions are x and y, then we have √(x^2+y^2) = x+8 xy = 60 You can grind out the solution, but I think you can recognize which factors of 60 form a convenient right triangle that works, no?
*July 28, 2016*

**Calculus**

dang those typos, yeah? 64 works much better.
*July 28, 2016*

**Calculus**

x+y=64 z = xy^3 = (64-y)y^3 = 64y^3 - y^4 dz/dy = 192y^2 - 4y^3 = 4y^2(48-y) I think the way is now clear, right?
*July 28, 2016*

**jeez - get it right, willya?**

and stop posting it!
*July 28, 2016*

**algebra - eh?**

how's that again? The product of two consecutive integer is 5 three times the larger integer
*July 28, 2016*

**Math**

just remember that revenue = price * no.tickets.sold You can use that to answer all these questions. Give it a try, and come back if you get stuck. also, recall that the vertex of a parabola ax^2+bx+c is at x = -b/2a. For R(x), that is where the maximum revenue occurs.
*July 28, 2016*

**physics**

v = √(2as) = √(2*9.8*20) = 19.80 m/s Now use that to answer the other question.
*July 28, 2016*

**math**

can't see hwy you don't just write the fractions, like 1/3, 2/√5, etc. Anyway, since volume is length * width * height then if one or more of those dimensions are scaled by a factor of r,s,t respectively, then the new volume is (length*r)*(width*s)*(height*t) = (...
*July 28, 2016*

**Algebra 1**

After n years, v = c(1-r)^n = 20000 * 0.79^n no need to subtract from anything, unless you want to see how much its value has declined. 6154.11 is the value after 5 years.
*July 28, 2016*

**Maths**

try using the sum-to-product formulas. If you get stuck, come on back and I'll see what we can do with what you have so far. I see google has some good discussions.
*July 28, 2016*

**Maths**

cos3x = cosx(2cos2x - 1) similarly, cos6x = cos2x(2cos4x - 1) I think you can see where this is going, right?
*July 28, 2016*

**Maths**

google is your friend many proofs online
*July 28, 2016*

**pre cal**

the asymptotes mean y = ??? / (x+2)(x-1) y(0)=0, so y = ax / (x+2)(x-1) y(2) = 12, so 12 = 2a/4 a = 24 y = 24x / (x+2)(x-1)
*July 28, 2016*

**pre cal**

vertical asymptote at x=6 and a horizontal asymptote means y = a(x-b)/(x-6) + c y(5) = 0, so b=5 y = a(x-5)/(x-6) + c y(0) = -5/6 and y(∞) = -1, so 5/6 a + c = -5/6 a + c = -1 1/6 a = -1/6 a = -1 c = 0 y = (5-x)/(x-6)
*July 28, 2016*

**math**

2 + 2 sinθ = 3 cos^2θ 2 + 2sinθ = 3 - 3sin^2θ 3sin^2θ + 2sinθ - 1 = 0 (3sinθ-1)(sinθ+1) = 0 sinθ = 1/3 sinθ = -1 so, there are two solutions for sinθ = 1/3 (QI and QII) and one solution for sinθ = -1
*July 28, 2016*

**basic maths trignometry**

secx - tanx = 1/cosx - sinx/cosx = (1-sinx)/cosx now use the double angle formulas to make that 1 - 2sin x/2 cos x/2 ------------------------- 2 cos^2 x/2 - 1 divide by cos^2 x/2 to get sec^2 x/2 - 2tan x/2 ----------------------------- 2 - sec^2 x/2 1+tan^2 x/2 - 2tan x/2...
*July 28, 2016*

**math**

5*4/5 = 4
*July 28, 2016*

**Math**

45/9 = x/12 x = 60
*July 28, 2016*

**math**

Oops. r=16% I calculated with r as the 6-month interest rate.
*July 28, 2016*

**math**

6250(1+r/2)^2 = 6760 r = 8%
*July 28, 2016*

**Maths**

For ease of reading, I'll just use s for sinx and c for cosx (1+s-c)/(1+s+c) = (1+s-c)^2/[(1+s)^2-c^2) = (1+s-c-sc)/(s+s^2) = (1-c)(1+s)/(s(1+s)) = (1-c)/s That means that [(1+s-c)/(1+s+c)]^2 = (1-c)^2/s^2 = (1-c)(1-c) / (1+c)(1-c) = (1-c)/(1+c)
*July 27, 2016*

**Maths**

I assume you mean arctan(x)+arcsin(x)=3/4 π well, you know that π/4 + π/2 = 3/4 π so, x=1 the hard way: sin(arctan(x)+arcsin(x)) = 1/√2 sin(arctan(x))cos(arcsin(x)) + cos(arctan(x))sin(arcsin(x)) = 1/√2 Now draw the right triangles for arctan(x...
*July 27, 2016*

**pre cal**

f(x) = a(x+5)(x-2)(x-4) f(-10) = a(-5)(-12)(-14) = -840a = -4 a = 1/210 f(x) = 1/210 (x+5)(x-2)(x-4)
*July 27, 2016*

**Algebra**

Well, you found the midpoint wrong. It is (-7.5,2.5) unless there's a typo in the coordinates. clearly x+y = -12 is wrong, since -8+4 = -4 That should have been your first clue. Using correct midpoint, the slope is -3. So, the answer is y-4 = -3(x+8) y-4 = -3x-24 3x+y = -20
*July 27, 2016*

**Maths**

I'll get you started. These problems are all about the same. The percent change is the amount pf the change divided by the starting amount. In this case, the two changes are (100-120)/120 = -20/120 = -1/6 = -16.67% (80-100)/100 = -20/100 = -20%
*July 27, 2016*

**Geometry**

it's a dilation, not a translation. for a dilation, each coordinate is multiplied by the scale factor.
*July 27, 2016*

**Algebra**

sina = cos(π/2-a) cosa = sin(π/2-a) 1+sina+icosa = 1+cos(π/2-a) + i sin(π/2-a) = 1 + cis(π/2-a) There is no simple cis(x) form because of that pesky 1.
*July 27, 2016*

**Math**

6n - 2(n-1) = 4n+2
*July 27, 2016*

**math**

(x)+(2x-32)+(x+18) = 534 Solve for x, and then the 3 parts.
*July 27, 2016*

**F/maths**

let the time spent on XY and YZ be a and b, respectively. Then on XY: s = 5a + a^2; v@Y=5+2a on YZ: s = (5+2a)b - 7/4 b^2; v@Z=0 Then we have 5a + a^2 + (5+2a)b - 7/4 b^2 = 475 5 + 2a - 7/2 b = 0 Just solve for a and b, and then you can answer the questions.
*July 27, 2016*

**maths - eh?**

eh? √16 = √4 ?
*July 27, 2016*

**Math**

This can also be seen by noting that a^2-b^2 = (a+b)(a-b) In this case, since the numbers are consecutive, that is just S*1 = S
*July 27, 2016*

**chemistry**

counting the moles, if there are x L of 6M HCl, then 6x + 2(2-x) = 3*2
*July 27, 2016*