Thursday
April 17, 2014

Posts by Steve


Total # Posts: 21,708

Algebra
4(6x^2-x-2) 4(3x+2)(x-1)

Math Geometry
x * (5/4)x = 180 x^2 = 144 ...

Calculus Help Please!!!
y' = 8x-6x^2 so, at x=a, y' = 8a-6a^2 = m Use the above info to plug into the point-slope form of the lines. No sweat.

Math
The key here is to recognize that opposite angles are supplementary. So, BAD+BCD = 180 2BAD=3BCD, so BCD = 2/3 BAD 5/3 BAD = 180 BAD = 108

Calculus Help Please!!!
(c) (15005-10237)/2 = 2384 (d) (16684-12435)/2 = 2124.5 (e) Looks like growth is slowing down

Algebra - help
just add them up: 3.1x^2+6x+0.3 4.2x2-5.2x+1 ---------------------- 7.3x^2+0.8x+1.3

Algebra
well, just plug it i: S = 4 pi (4x+1)^2 now just expand that

Math
n Tn 1 3*1+5 = 8 and so on actually, assuming one choice is correct, only B is a candidate.

math
(7y+4)(y-8)

Math - incomplete
well, with the four scores given, the average is already 75. I think some info is missing.

Math
since the period is 60/3.6 seconds, and reaches a max at t=12 seconds, y = 35cos(2pi/(60/3.6)(t-12))+51 which agrees with your formula. You have found y at t=8 seconds, not 8 minutes.

math
(6-4.5)/4.5 = 1/3

Science
Felipe made a toy boat out of clay, but it kept sinking in water. He changed the boat's design by making it slightly wider than before. Why did Felipe's newly designed boat float on water? A. He decreased the density by increasing the volume. B. He decreased the densit...

Trigonometry
C = 24pi in = 2pi ft (20 ft/s)/(2pi ft/rev) = 10/pi rev/s * 2pi rad/rev = 20 rad/s

Trig
no. sinA = 2 sinB

math
11/4

Algebra word problems
5x+20y = 175 x = 4y+3 Now just solve for x and y

math
yes

math
-y/6 < 2 y/6 > -2 y > -12

math
2/5 n = 4 n = 10

Algebra 1
RA = 11 RT = 1

Math
since the height of the ball is y = Ho + (tanθ)x - g/(2 (v cosθ)^2) x^2 y = 50 + .1175x - .000563x^2 Just solve for θ in 50 + (tanθ)(420) - 16/(2(120 cosθ)^2) * 420^2 = 0 I get θ = 6.7°

Algebra
7x*11x - 2x*3x = 71x^2

Math
1/2 dozen, no?

Polymonial help
Can you not? My factorization gives the three dimensions. Look at the last choice.

Polymonial help
factor the polynomial and you have y(y-6)(y+1) so, as long as y>6 some possible dimensions are 7x1x8 8x2x9 ...

Math
compare the times. The time it took to cover 100km at speed s is 100/s That was 1/2 hour more than the time it took to cover 100km at the faster speed, s+10

Math
since time distance/speed, 100/s = 100/(s+10) + 1/2 s = 40

math
(sum(r) for r=1..n)^2 - (sum(r) for r=1..n-1)^2 = n^3 well, we know that n ∑ r = n(n+1)/2 r=1 so, square that and we have n^2(n+1)^2/4 Sum to n-1 instead of n, and we have (n-1)^2 n^2/4 Subtract to get n^2/4 ((n+1)^2 - (n-1)^2) = n^2/4 (4n) = n^3

ASCC
25 m/s / 2.3 m/s^2 = 10.87 s distance = 25t - 1.15t^2 where t = 10.87

Math
no diagram. If the angles are alternate interior/exterior angles, then 5x+2 = 3x+28 If they are adjacent angles, then 5x+2 + 3x+28 = 180

Math Help
since the bus catches up 175 km in 5 hrs, that's a speed difference of 35 km/hr. So, the bus went 10+35 = 45 km/hr Your solution is in error. It should be 225km/5 hr = 45 km/hr (Also, the units are wrong in your 1st line: 10km/hr * 5 hr = 50 km, not 50km/hr) another soluti...

Geometry
That's what I get.

math 100
|3x-10) > 2 either 3x-10 > 2 3x > 12 x > 4 or -(3x-10) > 2 3x-10 < -2 3x < 8 x < 8/3 If you look at the graph you can see why an abs val > n problem usually has two solutions. http://www.wolframalpha.com/input/?i=+|3x-10|+%3E+2

maths literacy - still incomplete
no matter how many times you ask it, there is still not enough information to answer the question.

math - incomplete
none, if they all die.

math 100
50 < 40 + .25m

Maths
x + 2x-8 = 178

math - eh?
What's all this nonsense with ;;;? Just use + signs! If you mean the sum of x^2 / ((x-1)+x+(x+1)) that's kind of weird, since it boils down to x^2/3x = x/3 Naturally, the sum will be infinity. And what do you mean "find the value of x"? We are adding up all t...

Math help, anyone?
very good. B is the answer

Math help, anyone?
well, I just said that "right" refers to angles, not sides. So, #1 and #3 are out. Other kinds of angles are acute and obtuse. So, rather than just guessing, why not check on the terms being used?

Math help, anyone?
actually, a right triangle contains a right angle, so it does not fit into the category of triangles classified by sides. We aren't talking about angles. So, questioner, just look up the terms listed, and see which ones only talk about the sides of a triangle.

algebra
well, geez. The slope-intercept form is y = mx+b where m is the slope and b is the intercept. Which answer has slope 2/7 and intercept at y=12?

Statistics
Pick any person. There are 16 people to shake hands with. Since there are 18 people, there are 18*16 shakes. But, counting this way, each shake is counted twice, once for each person. So, the final answer is 18*16/2

Surds please help!
(√a + 3√b)/(a-b) - 2/(√a+√b) Note that (√a-√b)(√a+√b) = a-b, so (√a + 3√b)/(a-b) - 2/(√a+√b) * (√a-√b)/(√a-√b) (√a+3√b)/(a-b) - 2(√a-√b)/(a-b) (√a+3...

function table
well, what's 2*50 - 7 ?

Maths
n-30 = 14-3n n = 11

Math
26

math
If Mickey has x books, then x + 3x - 1 = 27 x = 7

Inverse laplace
Recall that L{tf(t)) = -F'(s) Since L^-1{1/(s-1)} = e^t and d/ds 1/(s-1) = 1/(s-1)^2 L^-1{1/(s-1)^2} = te^t

pre-calculus
147b^3-35b^2-19b+3 = 0 Since 147 = 7*7*3, I'd try using those coefficients first, since the inside coefficients are relatively small. A little playing around shows that T(b) = (7b-1)(7b-3)(3b+1)

algebra
Assuming you want the length of each piece, 1/2 = 9" 3/4 of that is 6 3/4 " The rest is thus 2 1/4 "

math
k(1-3/7) = -6/7 4/7 k = -6/7 4k = -6 ... 6.4x-x = -3.4+3.5 5.4x = 0.1 ...

math
900*1600*3 * 5.20

math
#1 depends on how many he wants to by count * cost <= 35.0 #2 4h <= 25

math
use the scale which allows both dimensions to fit: 8.5/100 or 11/150

MAT-134 Math XL
3x^7 - 9x^6 + 24x^5 3(x^7-3x^6+8x^5) 3x^5(x^2-3x+8)

Math
you can find Z-table help here: http://davidmlane.com/hyperstat/z_table.html you know the mean is midway between these two extremes. Use the tool to find how many STD's that is, then scale up to find the real score range.

algebra 1
x^5 + 5x^3 + 4x - 8 descending powers of x

Math
pick any value for x. Small values are easy to work with. Calculate the value for y. Plot the point. x y -4 3 -3 0 -2 -3 -1 -4 0 -3 1 0 2 3

Algebra 2
4/3 pi (r+6)^3 = 4/3 pi r^3 + 336pi 4(r+6)^3 = 4r^3 + 1008 now just solve for r

Math help
well, no. If the product of some numbers is zero, then one of the numbers must be zero. We have (3s-4)(2s-3) = 0 So, we must have either 3s-4 = 0 or 2s-3 = 0 So, s = 4/3 or 3/2 Had you tried your guesses in the original equation, you would have seen they did not satisfy it.

Math help
set everything to zero, then you can factor. #4 6s^2-17s+12 = 0 You know the factors will look like (6x-?)(x-?) or (3x-?)(2x-?) So, since -17 is fairly large, we will probably have the first (6s-3)(s-4) gives -27s too big (6s-4)(s-3) gives -22s still too big (6s-6)(s-2) gives ...

Math
Hmmm. x^4 + 10x + 18 - (x^4 - 3x + 2) does equal 13x+16 see what a difference some parentheses can make?

calculus
Hmmm. I get y = -x^3+bx^2+cx+d y' = -3x^2+2bx+c y" = -6x+2b inflection at x = -2 means -6x+2b = 0 b = -6 y = -x^3 - 6x^2 + cx + d extrema at x = -5,1 y' = (x+5)(x-1) = x^2+4x-5 we need -3x^2, so y' = -3x^2-12x+15 so c = 15 y = -x^3 - 6x^2 + 15x + d f(2) = 11, ...

Math
well, if yo know the measure of angle 5, then you can solve for x. For instance if <5 = 50°, x=13

Algebra
A taller people usually weigh more

Algebra
what association would you expect if you were graphing height and weight a- positive b- non-linear c- negative d- none of these my answer is a

Agent HELP! Trigonometry
Draw the altitude to the base. Then, if the angle is x, sin(x/2) = 5/17 now you know x/2, so just double it.

Trigonometry
sin67° = .92 48*.92/58 = .73 so, now you know sin A = .73 no sweat to find A now, eh?

algebra
reseller, not "retsilor" algebra, not "a" 15 * 1.30 = ?

math
local/foreign = 7/4 (local-8)/(foreign-8) = 9/5 local = 224 foreign = 128 now find your answer.

Math 110 - incomplete
depends on how many you have already taken.

Algebra
just multiply them all together.

Math
well, how many tiles does it take to cover a side and an end? Double that and add one for each corner.

Alg help
I get √241 = 15.52

Algebra 2
Plug in the (x,y) values and see whether they fit your equations. -3(-5) + 1 = 6? No (1/2)(1) - 3/4 = 4? No (5/3)(5)-17/3 = 10? No Try again, and show your work; you evidently need some coaching and study.

math please help
T >= -20

math
plug in your data at http://davidmlane.com/hyperstat/z_table.html It is an excellent tool

Math
the slant height is the height of each triangular face. Since you know how to find the area of a triangle, multiply that by 4, the number of faces.

algebra - incomplete
Got to know how high the 30th floor is.

Algebra
what is the formula used to calculate the lateral area for a square pyramid?

Algebra
what is the formula used to calculate the surface area for a square pyramid?

Algebra
what solid has 2 bases that are triangles and 3 lateral surfaces that are rectangles a- triangular pyramid b- rectangular prism c- triangular prism d- rectangular pyramid my answer is C

Algebra
if you go calc101.com and click on the long division link, you can see all the details and try other examples.

algebra
since y/x is constant, 2.52/8.4 = y/2.7 y = 0.81

Math
You have to ask yourself how much work gets done in 1 minute. Mr Baily can do 1/90 of the total in a minute. Add to that the amount that his son does in a minute. The sum is how much of the job gets done by both together. SO, if 1/3 gets done in a minute, the job takes 3 minut...

Math
1/x = 1/90 + 1/75 x = 40.9

Math
correct

algebra
no if there are any constant terms, the variation is not direct. You need y = kx for some value of k

math
If there were 5 tests, with average a, then compare total points earned: 5a - 60 = 4(a+5) 5a-60 = 4a+20 a = 80

math
current value is 10d+25q 10d+25(1.1q) = 1.075(10d+25q) 10d + 27.5q = 10.75d + 26.875 .625q = .75d q/d = .75/.625 = (3/4)/(5/8) = 6/5

geometry
h/2.8 = sin 25°

Maths
correct, if you meant 170,000

math
ʃ 1/4 sin^2(2x) dx = 1/8 ʃ 1 - cos(4x) dx = 1/32 (4x - sin 4x) + C

pre calculus
assuming a proper allocation of papers and distance, then 1/x = 1/70 + 1/80 x = 112/3 minutes

pre calculus
1000x + 2000(x+.005) = 190 x = 6%

Math
draw a diagram, as usual. If the tower has height h and the wire is meets the ground at distance d, h/d = sin 52 h/(d+32) = sin 21 eliminate d and you have h/sin52 = h/sin21 - 32 now just solve for h

Math
1/2 pi (24/2)^2 = 72pi in^2 Maybe in this case it actually should be 72 pie !

math
If you mean (as in area of trapezoid) h = 2A/(b1+b2) hb1 + hb2 = 2A hb1 = 2A-hb2 b1 = (2A-hb2)/h

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