Monday

March 2, 2015

March 2, 2015

Total # Posts: 29,297

**Math**

<7,-3> + 3<-2,4> <7,-3> + <-6,12> <1,9>
*February 18, 2015*

**geometry**

since the three angles sum to 180, they cannot all be over 60.
*February 18, 2015*

**Geometry (math)**

just subtract the smaller circumference from the larger. The difference is how much farther the longer hand travels. Odd, how you did the hard part, but then got stuck on the simple subtraction.
*February 18, 2015*

**Quadratic equations**

Ok. So, the revenue is the price times the attendance: (20-.80(y-150))(y) for y >= 150 You sure there's no typo? I get a maximum revenue for y < 150. Maybe the first 150 still get charged $20, but the extras get charged less. In that case, for y>150, the revenue ...
*February 18, 2015*

**Math**

wall area: 2.5m * 5.5m = 13.75 m^2 paintings: 4*1.25*2/3 = 3.33 m^2 so, what's the difference?
*February 18, 2015*

**Calculus Physics**

since a = x" = 6-24t a(7.8) = -181.2 F = ma = -670.4 N
*February 18, 2015*

**Physics - incomplete**

Sorry, F1 is not shown here.
*February 18, 2015*

**Math - still bogus**

If the perimeter is 39, and P is inside RXA, there is no way that PX can be 49. That's greater than the sum of all the sides of the triangle!
*February 18, 2015*

**Calculus**

Rats. I did it about the x-axis. Still, you see the method. Redo the rotation, and see whether you come up with 72π
*February 18, 2015*

**Calculus**

I assume that the line x=0 is also part of the boundary. If so, you just have a cone with radius 24 and height 3, with a volume of v = π/3 * 24^2 * 3 = 576π Oh, ok -- if you want to use calculus, then using discs of thickness dx, v = ∫[-3,0] πr^2 dx where ...
*February 18, 2015*

**Algebra**

pick any pairs (x,y) of values you want, as long as y = 3/5 x - 3 (0,-3) (5,0) ... There's only one solution set, however. It has infinitely many members, each obeying the rule 3x-5y=15.
*February 17, 2015*

**Mathematics**

m? m? we don' need no steekeeng m!
*February 17, 2015*

**math**

I assume you meant both points to be at 36°N. They are 180° apart in longitude. A good discussion on the topic can be found at http://www.movable-type.co.uk/scripts/gis-faq-5.1.html or any number of other hits by google.
*February 17, 2015*

**Math 222**

eh? It's just what you wrote. If you want to factor it, then you have a^2b(a^2+b^2)
*February 17, 2015*

**Math 222**

two factors of 45 are 3 and 15, which add up to 18. So you have (z+3)(z+15)
*February 17, 2015*

**physics**

suppose an observer were sitting still directly behind you. He would see the ball receding at 20-4 = 16 m/s. Instead, he sees the ball approaching at 2.5 m/s. So, his velocity is 16+2.5 = 18.5 m/s in your direction. What's with the ratios? We're not talking about ...
*February 17, 2015*

**Pre-Calculus**

you're kidding, right? Remember your algebra I? I didn't add 1/5, I subtracted 2/5 from both sides, and added r to both sides!
*February 17, 2015*

**Pre-Calculus**

Having answered #1 correctly (divergent because |r| > 1), how an you then be happy with the sum of an infinite series where r = 1.5? -45 = -18/(1-r) 1-r = 2/5 r = 3/5
*February 17, 2015*

**Math**

not quite. There is 1/3 of a piece left over, which is 3/4 of a foot, or 9 inches.
*February 17, 2015*

**Algebra**

(4p-1)(4p-1)
*February 17, 2015*

**Math**

I can only guess what is wanted. If 2/3 of the pizza is eaten, the angle of the piece (1/3) remaining is 120 degrees.
*February 17, 2015*

**Calculus**

4x^3 + 6
*February 17, 2015*

**Math**

300*520 + 600*480
*February 17, 2015*

**Calculus Chain rule**

not 6. It's -5 - 1 = -6
*February 17, 2015*

**math - relations and functions**

(x,y): (1,2),(2,4),(3,9) are 3 ordered pairs. It is a function because no single value of x maps to more than one value of y. Looks like time to review the discussion of functions in your text.
*February 17, 2015*

**calculus 3**

the vertical speed of the ball is 55 sin 25° = 23.24 m/s So, the height y is y = 23.24t - 16t^2 The horizontal speed is a constant 49.85 m/s (b,a) find when y=0 x = 49.85t (c) max height at the vertex of the parabola (d) assuming the same 55 m/s initial speed, find t when ...
*February 17, 2015*

**maths**

7^x + 4*7^x = 245 5*7^x = 245 7^x = 49 since 49 = 7^2, x=2 x-√x+20 = 0 think of this as (√x)^2 - √x + 20 = 0 I think you must have a typo. It is much better if you have (√x)^2 - √x - 20 = 0 (√x-5)(√x+4) = 0 √x = 5 or √x = -...
*February 17, 2015*

**calculus**

This is just like the last one, but oriented the other way. The graphs intersect at x = -3 and 4. So, the area is just ∫[-3,4] f(x)-g(x) dx where f(x) = (16-x^2)/2 g(x) = (4-x)/2
*February 17, 2015*

**Calculus**

the curves intersect at y = (-1-√13)/2 and (-1+√13)/2 area is thus ∫[(-1-√13)/2,(-1+√13)/2] (-y+3)-(y^2) dy
*February 17, 2015*

**Calculus**

3y = -3y + 9 ??? Fix that. Then, find where the two graphs intersect. Since the parabola opens to the right, it's easier to integrate along dy. The area is just a bunch of thin strips of height dy and length the distance between the two curves. Express that and integrate ...
*February 17, 2015*

**math**

If a book has 10 pages, and there are 6 books, can you find the total number of pages? I expect so. You just multiply the number of pages by the number of books. Same here. Just multiply the number of apples by the number of containers. So, what is 1/3 times 6?
*February 17, 2015*

**imp**

If you want to dig up the dirt on someone, then it becomes just information, a more abstract quantity. Many nouns in English have several meanings, some concrete, others more abstract, or metaphorical.
*February 17, 2015*

**kayli**

maybe it was a cold day, but the sun was shining on the table. The drink shaded a spot on the table, so sunlight no longer warmed the spot. The drink was in an insulated cup, so it did not absorb any heat.
*February 17, 2015*

**maths**

Hmmm. OK. In that case, the two circles must be orthogonal to each other. That is, if you draw triangle acb and adb, each is a 3-4-5 right triangle. The common chord is just twice the altitude to the hypotenuse, which I'm sure you can find.
*February 17, 2015*

**maths**

how can a line though the center (ac) be a tangent to the circle?
*February 17, 2015*

**Math**

you are correct. A dilation might be around some other point, in which case distances to that point are scaled, and things get much more complicated.
*February 17, 2015*

**Math**

Let the boxes be E,O,M. Draw a ball from E. If it is even, then the box marked O must contain the even balls, because otherwise the M box would contain the evens, leaving O containing the odds. But O is mislabeled, so it must contain the evens. So, drawing an even ball from ...
*February 17, 2015*

**Calculus**

well, where is cosx a maximum? At x=0. So, at x=0, the slope of 2sinx = 2. 2sin(0) = 0, so, at (0,0) the slope is 2. The line is y=2x. By now you should know that sin(x) has its maximum slope where it crosses the x-axis. That's what we have calculated here.
*February 17, 2015*

**Science**

I agree with D
*February 16, 2015*

**calculus**

s= [b]*[d]+64t-16t^2 what is the greatest height above the ground the rock will go
*February 16, 2015*

**Precalc**

Are you confusing k and θ? I see no k in the function. It also appears you are missing some information. Ought we not to know S?
*February 16, 2015*

**calculus**

well, you should start out by solving the DE: P = 10/(1+c*e^(-t/5)) (A) P(0) = 3, so 10/(1+c) = 3 c = 7/3 P(t) = 10/(1 + 7/3 e^-t/5) Now it's clear that P->10 Now try the rest.
*February 16, 2015*

**Pre calculus**

Draw a diagram. Label the angles in the drawing, and you will see that the angle you must use is 180-38-35 = 107° Be sure to note that the current is coming from the direction of 125°. That means the current's flow is in the direction 305°.
*February 16, 2015*

**Algebra 1**

the differences are constant, so the function is linear. The slope is 50/2 = 25 I don't see any likely choice. I suspect a typo.
*February 16, 2015*

**Algebra 1**

The attendances at a high school basketball games seems to be affected by the success of the team. Look at the table and decide what function would represent the data shown. attendance 150 200 250 300 350 wins 2 4 6 8 10 a) a=2(3)^g b) a=-25g+100 c) a=25g^2+100 d) a=-25g^2+100
*February 16, 2015*

**GEOMETRY**

the legs and hypotenuse of a 30-60-90 triangle are in the ratio 1:√3:2 so, depending on whether the 7√3 leg is the short one or the long one, w could be 14 or 14√3
*February 16, 2015*

**math**

sin 30° = cos 60°, so x=30.
*February 16, 2015*

**ALGEBRA**

looks like (b) to me. 1/2 x would leave extra 1/2's at all the odd values of x.
*February 16, 2015*

**Physics**

conserve momentum 3.5*24 = m*320
*February 16, 2015*

**maths**

If I understand you to mean that AB┴AD and BC, then BC-AD=12 and h=AB=√(19^2-12^2)=√217 so, the area is (42+54)/2 √217
*February 16, 2015*

**MAth**

clearly, tax was included . . .
*February 16, 2015*

**math**

The room was measured to be 20 by 30 m. So, just multiply each dimension by 0.95 to find the true area. Or, just do it in one step: 600 * 0.95^2
*February 16, 2015*

**maths**

the difference in height is 30. So, draw a diagram. The rope is the hypotenuse of a 30-40-50 right triangle.
*February 16, 2015*

**College Algebra**

x(x-2)(x-9) = 0
*February 16, 2015*

**Calculus**

wow! what a lot of work. juat factor out the cosx and expand the (1-sin^2 x)^3
*February 16, 2015*

**Calculas**

what you have is cosx (1-sin^2 x)^3 dx Now expand the polynomial, and each power is sinx is accompanied by cosx, which is just d(sinx).
*February 16, 2015*

**Algebra 1**

me too.
*February 15, 2015*

**Algebra 1**

Which kind of function best models the set of data points: -1,22 0,6 1,-10 2,-26 and 3,-42? linear quadratic exponential non e of the above my answer is linear
*February 15, 2015*

**math analysis**

how about a few parentheses, so we can see just what is divided where... I mean, secs/secx = 1
*February 15, 2015*

**math**

R is 3/7 of the way along S is 5/7 of the way along RS is the difference: 2/7 * 8 = 16/7 cm
*February 15, 2015*

**Calculus**

well, you have calculated where the extrema occur, so just plug in the values for x and calculate f(x). or, you can easily see the values because sinx-cosx = √2(sinx/√2 - cosx/√2) = √2(sinx cos π/4 - sin π/4 cosx) = √2 sin(x-π/4) ...
*February 15, 2015*

**Algebra 1**

How many solutions are there form 5x^2+7x-4=0? my answer is 3
*February 15, 2015*

**Algebra 1**

thank you
*February 15, 2015*

**Algebra 1**

Which method is the best method for solving the equation 8x^2-123x+3=0 square roots factoring graphing quadratic formula my answer is quadratic formula
*February 15, 2015*

**Math**

enter your functions here and see the steps: http://maccery.com/maths/#newton-raphson
*February 15, 2015*

**math**

3-2x < x <= 2x+5 3-2x < x 3 < 3x 1 < x x <= 2x+5 -x <= 5 -5 <= x combine them and you are left with x > 1
*February 15, 2015*

**algebra**

5/(6x-1) = -1/(x+1) Just clear denominators as usual. Suppose you had 3/8 + 2/3 You multiply by 3/3 and 8/8 so you have 3*3/24 + 2*8/24 So, for your equation, multiply to use the common denominator (6x-1)(x+1) 5/(6x-1) = -1/(x+1) 5(x+1)/[(6x-1)(x+1)] = -1(6x-1)/[(6x-1)(x+1)] ...
*February 15, 2015*

**multivariable calculus**

just review your spherical coordinates. I'm sure the relevant section justifies the claim.
*February 15, 2015*

**Pre-Calculus**

sequence converges series diverges (unless a=0)
*February 15, 2015*

**Computer Science**

if the original price is $100, the final cost is $91.
*February 15, 2015*

**maths**

#1 for n odd, Tn = 3n-2 For n even, Tn = 1/2^n #2 r^3 = T7/T4 = √81/√3 = √27 r = √3 Now you can find a
*February 15, 2015*

**maths(urgent answer pls)**

n ∑ (2k-1)/[k(k+1)(k+2) = k=1 n(3n+1) -------------- 4(n+1)(n+2)
*February 15, 2015*

**math help**

where is P?
*February 15, 2015*

**Math**

use both equations. e^.04t < 6 for t < 45 http://www.wolframalpha.com/input/?i=plot+15%2Be^%280.04t%29+sin%28pi*t%2F3%29%2C+15%2B6*sin%28pi*t%2F3%29
*February 15, 2015*

**math**

calculate f(2) and f(3) If the value changes sign, then the graph must cross the w axis somewhere in the interval, since f(w) is continuous there.
*February 15, 2015*

**maths**

the area of metal is the area of the small circle plus the area of the sides. The small circle has area 49π Now for the sides. Consider the entire cone with base radius 28 and height 4h. Chop off the top 1/4 of the height, and the missing volume is (1/3)π*7^2*h The ...
*February 15, 2015*

**maths**

h/35 = tan 57°40'
*February 15, 2015*

**mathematics**

Sn = 5/2 n^2 + 7/2 n = n/2 (5n+7) Sn = n/2 (2a+(n-1)d) 5(n-1)+5+7 = 5(n-1)+12 a=6 d=5 T10 = 12+9*5 = 57 check: 6 = 1/2 (12+0) 6+11 = 17 = 2/2 (12+5) 6+11+16 = 33 = 3/2 (12+10) looking good.
*February 15, 2015*

**mathematics**

Better clarify just what 3/5/9 means.
*February 15, 2015*

**mathematics**

ar = a+4 ar^2 = ar+9 r = 9/4 a = 16/5 so, now figure the first 3 terms.
*February 15, 2015*

**math**

the volume of the liquid of height h is v = πr^2*h also, v = (384g)/(0.6g/cm^3) So, equate the two, plug in r, and solve for h.
*February 15, 2015*

**Pre-Algebra**

As always, draw a diagram. Using similar triangles, it is clear to see that 4/5 = (x+4)/15
*February 15, 2015*

**math**

you are apparently using logs base 10, so log 0.096 = log(96*10^-3) = log96 - 3 = log(16*6)-3 = 2log4 + log6 - 3 ...
*February 15, 2015*

**math**

assuming the rectangle is long enough to wrap around the cylinder, a = πr^2 + πr^2 + 2πrh = 2πr(r+h) Now just plug in r and h.
*February 14, 2015*

**Calculus**

y = 3x 3^x - 1 y' = 3*3^x + 3x(ln3)3^x = 3*3^x * (1+x ln3) So, y'=0 when x = -1/ln3 That is the only extremum. Now find whether y" is positive or negative there to determine which kind.
*February 14, 2015*

**math**

An odd question. Since the vectors are independent, they span R^2, and the dimension is 2. Am I missing something here?
*February 14, 2015*

**calc**

does not matter. tan and arctan are inverse functions. tan(arctan(x)) = x As to how to find arctan(3) -- have you no calculator? There are gobs of them online if you do not.
*February 14, 2015*

**Math**

Naturally, that wold be f(w) = 0
*February 14, 2015*

**Math**

best convert to polar form z^4 = 46.87 cis 2.95 so, z = 2.62 cis 0.738 + k*pi/2 for k=0..3 then convert back to rectangular form.
*February 14, 2015*

**Math**

Hmmm. I can see that there could be two solutions -- one in front of the plane of the given points, and another behind it. But since the matrix has a linear determinant, I'm not sure how to get the other one. Need to think on that a bit.
*February 14, 2015*

**Math**

put the coordinates in columns of the matrix M: (2 6 3 x) (2 3 -1 0) (3 0 -1 0) (1 1 1 1) The volume of the tetrahedron is 1/3! |M| = 1/6 (13x-39) So, you want 1/6 (13x-39) = 26 13x-29 = 156 13x = 185 x = 14.23 google tetrahedron vertices volume and you can find several useful...
*February 14, 2015*

**a sond wave is prouduced. 3seconds later its echo**

the sound has to go out and back. SO, how far does sound go in 1.5 seconds?
*February 13, 2015*

**math calculus**

2^x is not the inverse of (1/2)^x log_2(x) is the inverse of 2^x log_1/2(x) is the inverse of (1/2)^x You can check this because if g(x) is the inverse of f(x), f(g(x)) = x and g(f(x)) = x (1/2)^x = 1/2^x they are reciprocals, not inverses.
*February 13, 2015*

**math calculus**

well, (1/2) = 2^-1 go to wolframalpha.com and enter plot y=2^x, y=(1/2)^x
*February 13, 2015*

**math**

do you actually read what I write? I explained k, and I used it. Don't make me do your thinking as well as your math!
*February 13, 2015*

**math**

so, if the dimensions are x and y, 50% increase of y is 1.5y. But, you want the new area to be the same. So, if x is multiplied by k, you want (k)(x)(3/2)(y) = xy (k)(3/2)(xy) = xy k(3/2) = 1 k = 2/3 So, if the new width is 2/3 of the old width, that is a decrease of 1/3, or ...
*February 13, 2015*

**math**

length is 3/2 so, width is 2/3
*February 13, 2015*

**math**

c-15 = (2/9)(c+15) + c/6
*February 13, 2015*

**math**

read what you wrote. There are no numbers given, yet you want a numeric answer? 42 is the answer to the Ultimate Question of Life, the Universe and Everything, so it surely must answer your puny question as well.
*February 13, 2015*

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