Wednesday
May 25, 2016

Posts by STEVE

Total # Posts: 40,816

math
original: n/d new: .5n/.75d = (2/3)(n/d) so, it is decreased by 33.3%
May 3, 2016

Math -Trig
for any x, cot(x) = 1/tan(x) 3pi/4 is in Quadrant II, so draw the triangle. x = -1 y = 1 cot(3pi/4) = x/y = -1/1 = -1 or, consider that cot(pi-x) = -cot(x) since cos(pi-x) = -cos(x) and sin(pi-x) = sin(x) so, cot(3pi/4) = cot(pi - pi/4) = -cot(pi/4)
May 3, 2016

Math - Trig
12 revolutions per minute 3.5*pi meters per revolution ...
May 3, 2016

math
Apparently greedy Ashley already had 1/4 of a pizza! anyway, 1 3/4 = 7/4 divide that by 11, as we're just talking about the friends.
May 3, 2016

half-life
.5mg is 1/8 of 4 mg 1/8 = (1/2)^3 so, that's 3 half-lives
May 3, 2016

math
60/36 ft * 12in/ft
May 3, 2016

maths
200 sin40
May 3, 2016

Math
1/6 of the time for each number.
May 3, 2016

math
11!/(2!2!2!2!) = 2,494,800
May 3, 2016

Calculus
see a nice calculator here to check your work: http://www.emathhelp.net/calculators/calculus-2/simpsons-rule-calculator/
May 3, 2016

math
(60 * 0.80 - 10) * 1.55 = $58.90
May 3, 2016

math
a = b + 0.50b = 1.5 b b = a/1.5 = 2/3 a so, b is 1/3 less than a, or 33.3% less
May 3, 2016

math
increasing by N% means the new value is 1+N/100 as much as the old value. So, we have new = old*(1+1)(1+1.5) = 5.00 * old so, old = new/5 or 20%
May 3, 2016

math
x * 1.25 = 2 x = 1.6 so, the first increase was 60%
May 3, 2016

urgent math
#1. 7^(9-3) = 7^6 NOT 7^(9/3) = 7^3 subtract exponents when dividing numbers. What you have is 7*7*7*7*7*7*7*7*7 ------------------------       7*7*7 only three of the 7's cancel #2 z^8/z^12 = 1/z^4 = z^-4 So, D, not C #3 ok #4 not sure what ...
May 3, 2016

Math
two adjoining trapezoids produce a figure with six sides. You only give four lengths. You will need to use the sides and the Pythagorean Theorem to determine the heights of the trapezoids. Then it's easy, since you know the formula for the area of a trapezoid, given its ...
May 3, 2016

Algebra
#10. since 1=√1, you must have -2v-3 = 1 #11. √(n+5)= √(5n-11) n+5 = 5n-11 n = 4 check: √9 = √9 #12. well, geez, just check them! √(12-(-4)) = √(12+4) = √16 = 4 Since this is not equal to -4, that value is extraneous. √(12-...
May 3, 2016

math
independent means they can both happen, and do not affect each other. Like two consecutive rolls of a die. Rolling a 3 and then a 6 are independent, and can both happen. Mutually exclusive events cannot both happen, such as flipping a coin and getting both a head and a tail. ...
May 3, 2016

Science
well, time = distance/speed, so just crank it out.
May 3, 2016

Math
(2 – 9c)(–8) 2(-8)+(-9c)(-8) -16 + 72c
May 3, 2016

Geometry/Trig
since the acute angles are 45°, the two legs are both 16 (a fact you left out) so, the hypotenuse is √(16^2 + 16^2) = 16√2
May 3, 2016

chemistry
moles KOH = .0175 * .553 = .00968 so, you need that many moles of HBr, making the molarity M = .00968/.025 = 0.387
May 3, 2016

Math
x - x/3 + 25 = 115
May 3, 2016

math 1324
x+y+z = 2000000 .07x + .085y + .095z = 169750 y = 4z see the matrix solution at http://www.wolframalpha.com/input/?i={{1,1,1},{.07,.085,.095},{0,1,-4}}*{{x},{y},{z}}+%3D+{{2000000},{169750},{0}} {{1,1,1},{.07,.085,.095},{0,1,-4}}*{{x},{y},{z}} = {{2000000},{169750},{0}}
May 3, 2016

Analytic Geometry
cot2θ = 0 so θ=45° Then just do the rotation matrix stuff to find the equation in the new coordinates.
May 3, 2016

math
won = 15+3*lost won + lost = 123 lost = 27 won = 96
May 3, 2016

math
3/200 = 1.5/100 = 1.5%
May 3, 2016

Math
tanx/sinx = 1/cosx cosx=0 at odd multiples of pi/2. So, that is where you have asymptotes. cosx changes sign at those points, so also does your graph.
May 3, 2016

math
depends on the area of the base. Divide the volume by the area to get the height.
May 3, 2016

math - eh?
huh?
May 3, 2016

math - Correction.
that is an obtuse angle. I'd say 0° < d < 90°
May 2, 2016

Maths
The three numbers will therefore be close to 21.98. So, I'd say they'd be 21,22,23 whose product is 10626
May 2, 2016

math
480ft/30s * 60s/min = 960 ft/min
May 2, 2016

math
not so. you have found d/dt (dy/dx), but you want d/dx (dy/dx) = d/dt(dy/dx) / dx/dt = -1/(1+t)^2 / e^t = -1/((1+t)^2 e^t)
May 2, 2016

TRIGONOMETRY2
can't use google? 1st hit led to http://www.cut-the-knot.org/proofs/2Colors2Points.shtml#solution
May 2, 2016

TRIGONOMETRY
√(x+b)-√(x-a) >= √(x+a)-√(x-b) since x>=a>=b, we have x+b >= 2b x-a >= 0 x+a >= 2a >= 2b x-b >= x-a see what you can do with that
May 2, 2016

Math
the ratios are: length: 11/33 = 1/3 width: 7/28 = 1/4 so, not similar
May 2, 2016

math
not quite. log(x^2) = 2logx 150 = 3*100/2, so log 150 = log3 + 2log10 - log2 75 = 3*(10/2)^2, so log75 = log3 + 2log10 - 2log2 or, since 75 = 150/2 log75 = log150-log2 as above
May 2, 2016

Probability
1/15000 (1000 + 2*300 + 20*10) = 3/25
May 2, 2016

Math
there is no limit. There must be some other considerations.
May 2, 2016

Geometry
well, just check. a sphere with diameter d has volume π/6 d^3 3*(π/6)(5^3) = 375π/6 (π/6)*8^3 = 512π/6 π/12 * 10^3 = 500π/6
May 2, 2016

calculus
94 ∑ k k=3 assuming you meant ... 144, 12 ∑ k^2 k=3
May 2, 2016

Algebra
y=5x
May 2, 2016

pre-cal
as they said, the total area is xy as for the print area, that is (x-2)(y-3) = 26
May 2, 2016

calculus
maximize p=x(30-x)-100-6x subject to x >= 10 x <= 20 the profit is revenue-cost, so p(x) = x(30-(x-10)) - 100 - 6x = -x^2+34x-100 dp/dx = 34-2x dp/dx=0 at x=17
May 2, 2016

calculus
this is just the chain rule in reverse. G'(x) = cos(x^2) (2x)
May 2, 2016

calculus
change all the t's to x^2, then multiply by (x^2)' G(x) = cos(x^2)(2x)
May 2, 2016

math
it is a function whose graph is s straight line.
May 2, 2016

calculus
Sketch the region. It has vertices at (0,0), (2,0), (4,2) You can get the area by using vertical or horizontal strips. Using vertical strips, they all lie below the curve √x, but the lower boundary changes from y=0 to y=x-2 at x=2. So, the area is ∫[0,2] √x ...
May 2, 2016

math
as usual, v = Bh = 20*10 = 200 cm^3 note that the area of the base must be in cm^2, not just cm.
May 2, 2016

Math
You have only listed 4 side lengths, so I'm not clear. But, to get the area, divide it up into triangles, and maybe rectangles, if there are any. Then just add up the areas of the pieces.
May 2, 2016

math
the base is 139.2/9.6 = 14.5 since all sides are the same, the perimeter is 4*14.5 = 58
May 2, 2016

algebra
(17-1)/(2-(-2)) = 16/4 = 4
May 2, 2016

calculus too hard help
Let's pick up at lny = x ln(y) 1/y y' = ln(y) + x/y y' y' (1/y - x/y) = ln(y) y' = y*ln(y)/(1-x) I'd suggest not looking too hard for a pattern. Pop over to wolframalpha.com and try entering x^x, then x^x^x, then x^x^x^x, and so on. The derivatives ...
May 2, 2016

Math
Thank you Reiny. That makes perfect sense to me. Next time I post a question I will think a little harder to possible ways of working questions like this. 😀😀
May 2, 2016

Math
When a telephone exchange is established, there are 10,000 new phone numbersto use(i.e. 722-0000 to 722-9999). Of these 10,000 phone numbers, how many do not contain the digit "9"? I know I can do it this long way, but how do I do it in a shorter more reliable way. ...
May 2, 2016

Calculus - urgent
Consider the mass as a bunch of horizontal strips, each with area (x2 - x1) dy and thus mass (x2-x1)y dy = y(√(1+2y/3) - (2y^2-y)) dy Now just integrate from 0 to 1.0989
May 2, 2016

trigonomentry...Very hard
theta, not tita. let x = 3tanθ x^2 = 9tan^2θ 9+x^2 = 9+9tan^2θ = 9sec^2θ √(9+x^2) = 3secθ so, draw a right triangle. Since tanθ = x/3, those are the two legs, and the hypotenuse is √(9+x^2) Now you can write down sinθ and cosθ
May 2, 2016

Geometry (answer please)
#1. well, each wire is the hypotenuse of a right triangle, with legs 16 and 10√2 back later for #2.
May 2, 2016

Math
surely, 3+3+3 feet, no? assuming the ribbon is to go once around the edges of the blanket...
May 1, 2016

Math
since u.v = |u||v|cosθ we must have cosθ = -1. In other words, v = -u
May 1, 2016

Algebra 1
B is good.
May 1, 2016

math
If you're using logs base 10, recall that log(32) = log(10*3.2) = log(10)+log(3.2) = 1+log(3.2) So, just look up log of 3.2 and add 1. Whoa - who uses tables these days?
May 1, 2016

Plane trigonometry
I don't know what "the five points" are, but here's the graph: http://www.wolframalpha.com/input/?i=2sin%28pi*%28x%2B1%2F2%29%29%2B1
May 1, 2016

trig
I'll use x for ease of typing tan(x)/(tan(2x)-tan(x)) tan(x)/((2tanx)/(1-tan^2(x))-tan(x)) tan(x)/((tanx(2/(1-tan^2(x)) - 1) 1/(2/(1-tan^2(x)) - 1) (1-tan^2(x))/(2 - (1-tan^2(x)) (1-tan^2(x))/(1+tan^2(x)) (1-tan^2(x))/sec^2(x) (1-tan^2(x))cos^2(x) cos^2(x)-sin^2(x) cos(2x)
May 1, 2016

Algebra
you are correct.
May 1, 2016

MEASUREMENTS
15m^2 * (3.28ft/1m)^2 * 1bag/20ft^2 * $2.00/bag = $16.14 you said M^2, then used YD^2. I used meters, but you can fix it. Your units do not work out right, and you lost the 15
May 1, 2016

Exponential Modeling
on the other hand, given the topic of the posting, 0.10(1+r)^40 = 1.25 (1+r)^40 = 12.5 1+r = 1.065 r = 6.5% per year
May 1, 2016

MATH
The scores are x x x x x x x x The median is 5, so they are x x x 5 5 x x x or x x x 4 6 x x x or 3 3 3 3 7 7 7 7 In the first case, 5 goals are scored. Otherwise, we need not have any scores of 5.
May 1, 2016

math
this is discussed at http://mathforum.org/sum95/suzanne/whattess.html google is your friend. Use it.
May 1, 2016

MATH- HELP PLEASE. IM LOST
the other side is either 3.7Ø or 3.7/Ø
May 1, 2016

Geometry ( helllppp pleaaassse )
#1. How can working with a single point on the ceiling tell anything about the length of the ceiling? #2. Drop the ladder to the floor, and mark where it hits. The use the ladder to construct a hexagon. Two of the main diagonals intersect at the center of the hexagon, just ...
May 1, 2016

Exponential Modeling
100 * (1/2)^7
May 1, 2016

Exponential Modeling
2000 * (1/2)^x
May 1, 2016

Exponential Modeling
p = 1013 * .88^x check for typos
May 1, 2016

Math
subtract 32 and multiply by 5/9 C = 5/9 (F-32)
May 1, 2016

Algebra
try this useful site: http://www.zweigmedia.com/RealWorld/LPGrapher/lpg.html
May 1, 2016

Math
5/6 * 1/2 = 5/12 you might as well ask, what is 1/2 of 5/6?
May 1, 2016

Math
a + a+d + a+2d = 24 a+3d + a+4d + a+5d = 51 now simplify the equations and solve for a and d.
May 1, 2016

Geometry
If the foot of the ladder started out at x ft away from the wall, then we know that the length of the ladder is 2x ft. With a 45° angle, then the two legs are x+8 ft, and the length of the ladder is (x+8)√2. So, now we have 2x = (x+8)√2 x(2-√2) = 8√...
May 1, 2016

Solid Mensuration
circles can be packed in many ways. If they are in a rectangular lattice then they may be in a 2x3 array, in which case, each circle's diameter is 1 foot. Surely by now you have made some attempt to solve the problem...
May 1, 2016

Matthhh
the straight-line distance is √(60^2+6^2) = 60.3 ft, so ...
April 30, 2016

Algebra
since there is a walkway on both sides, each dimension is increased by 2x. A(x) = (20+2x)(15+2x)
April 30, 2016

Algebra
since time = distance/speed, 6/(90-x) + 6/x = 4.5 x ≈ 1.35 km/hr
April 30, 2016

math
1 2 3 5 6 6 6 so, it can be 1. or even 1 5 5 5 5 5 6
April 30, 2016

Discrete Mathematics
26!/(8!12!6!) wow - who'd have thought that the entire set of books would contain only three different titles?
April 30, 2016

CES
1*22 + 9x = 8(x+22)
April 30, 2016

MATH
volume = 50*10*20 cm^3 1 liter = 1000 cm^3
April 30, 2016

algebra
I suspect the subtraction problem is 2x^2+5x-10 3x^2-x+9 ----------------- -x^2+6x-19
April 30, 2016

math
42 is the answer to the Ultimate Question of Life, the Universe and Everything -- surely it answers your feeble inquiry! Actually, I have no idea what you're talking about. which columns are you talking about? The only thing I can think of is that the line of cars looks ...
April 30, 2016

math
42
April 30, 2016

Math
well, 1 meter is 100 cm. So, how much is still needed?
April 30, 2016

rio claro west secondar
0.4^2 * 3.7 = 0.16 * 3.7 = ?
April 30, 2016

math
bzzt. The new value is 120% of the old one, so it increased by 20%.
April 30, 2016

math
3 of 8 = 3/8 = .375 = 37.5% t2o killed leaves 6 to share, so adjust the fraction. then subtract to find the change.
April 30, 2016

math
well, what are the nearby multiples of 500? ... 29,000 29,500 30,000 ... which is closest?
April 30, 2016

maths
you kidding me? You can't count by twos?
April 30, 2016

Maths
LCM(30,60,x) = 1500 30 = 2*3*5 60 = 2^2*3*5 1500 = 2^2*3*5^3 x could be 5^3 = 125 or any multiple of 25 consisting only of 2,3,5 as factors GCF(30,60,x) = 10 so, 125 is out, but 250 is in LCM(30,60,250) = 1500 GCF(30,60,250) = 10
April 30, 2016

Math
what is the difference between 6 and 10? How did you find it? Do the same step with the numbers above recall how to subtract negative numbers: 10 - (-5) = 10+5 = 15
April 30, 2016

Solid Mensuration
The diameter of the circle is 12 cm. The quadrilateral consists of two congruent triangles, with base 12 and altitude 4. So, its area is 48 cm^2
April 30, 2016

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