Saturday
February 13, 2016

Posts by STEVE

Total # Posts: 37,620

Algebra
since time=distance/speed, 40/(20-x) = 60/(20+x)
January 31, 2016

math
any number greater than 1 will work 1/5 < 2/7 < 1/3 1/5 < 9/35 < 1/3
January 31, 2016

Math
If the fast pump takes x hours, then 1/x + 1/(4x) = 1/4 Solve for x, and then use 4x as your time.
January 31, 2016

math
There are several useful formulas, though, such as a^2-b^2 = (a+b)(a-b) You have 16-36p^2 = 4^2-(6p)^2 = (4+6p)(4-6p) = 4(2+3p)(2-3p)
January 31, 2016

math
This kind of thing just takes practice. You know the factors will look like one of (12x-?)(x-?) (6x-?)(2x-?) (4x-?)(3x-?) where the two ? numbers are 1 and 5. Then it's just trial and error. Eventually you will wind up with 12x^2-23x+5 (4x-1)(3x-5)
January 31, 2016

Math
well, just use the given numbers. The ratio is 9.6/22.2 Now you can turn that into a simplified fraction by multiplying top and bottom by 10, the canceling common factors.
January 31, 2016

Algebra
Draw a diagram. That simple step will make solution a lot easier. A(x) = (20+2x)(15+2x) Now you can expand that to standard form.
January 31, 2016

engineering
well, uh, g, plug in the numbers! 20 miles = 32.2 km, so A(32.2) = 9.81(6380/(6380+32.2))^2 = 9.71 m/s^2
January 31, 2016

Calculus
f(-2) = (-2)^4 = 16 f'(x) = 4x^3, so f'(-2) = 4(-2)^3 = -32
January 31, 2016

calculus
x(2x)(z) = 36000 so, the height z is 18000/x^2 the area is 4x^2 + 2xz + 4xz the cost in centavos is c = 10*4x^2 + 5*2xz + 5*4xz = 40x^2 + 30xz = 40x^2 +540000/x = 40(x^2 + 13500/x) minimum cost is when dc/dx=0 dc/dx = 40(2x-13500/x^2) = 80(x^3-6750)/x^2 dc/dx=0 when x^3 = 6750...
January 31, 2016

Math Algelbra
since time = distance/speed, then the time for walk = 10/4 bike = 10/10 car = 10/40
January 31, 2016

Physics
you know the height y is y(t) = 1.5 + 30*.866t - 4.9t^2 = 1.5 + 25.98t - 4.9t^2 y(4) = 27.02 max height is y(2.65) = 35.94 vertical speed is 25.98-9.8*4 = -13.22 horizontal speed is 15.00 So, speed at impact is 20.00 m/s
January 31, 2016

Calculus and Vectors
see related questions below
January 31, 2016

Maths
well, just plug in the numbers! 1/3 * 24^2 * 30 = ?
January 31, 2016

Calculus Plz Help
see later repeat posting.
January 31, 2016

Geometry
the topic is discussed quite well at http://jwilson.coe.uga.edu/emt668/emat6680.folders/brooks/6690stuff/righttriangle/rightday3.html
January 31, 2016

Geometry
Thank you
January 31, 2016

Geometry
Draw a diagram. The answer is clearly (4)
January 31, 2016

Geometry
Which of the following represents the length of a diagonal of a trapezoid with vertices of (-b,c), (b,c), (-a,0), and (a,0)? 1- sq root (a+b)^2-c^2 2- sq root (a-b)^2 - c^2 3- sq root (a-b)^2 +c^2 4- sq root (a+b)^2 +c^2
January 31, 2016

Maths
3x-12 = (2/3)x + 16 now just solve for x.
January 31, 2016

maths
The way it is given, I expect the general rule is Tn = 4n-1
January 31, 2016

pre-cal
42
January 31, 2016

QMB
1st groups scores were more spread out, but generally scored higher.
January 31, 2016

algebra
Can't tell. I need to know the expected value of the mix, somewhere between $3 and $5 per lb. If its cost is to be $n/lb, then 5x + 3*10 = n(x+10)
January 31, 2016

caculas
see related questions below
January 31, 2016

mathematics
If you mean (6 to the power 5) ÷ (6³) + (7 to the power zero) or, losing all the static 6^5 / 6^3 + 7^0 = 6^2 + 1 = 37 You may group otherwise, but the evaluations of the powers will be the same.
January 31, 2016

Matrix question
yes. (AB)t = (Bt)(At) works like inverses.
January 31, 2016

math
well, 65=5*13 now you know the length and width, so ...
January 31, 2016

Matrix
(AB)t = (Bt)(At)
January 31, 2016

Math
right arm.
January 30, 2016

Math
the hypothesis is what you are not sure of. It is almost always preceded by "if." So, A
January 30, 2016

calculus
well, just set demand = supply and solve for p.
January 30, 2016

Algebra 1
If there are x correct answers, then there are 24-x mistakes. So, you need to solve 50x - 100(24-x) = 300
January 30, 2016

PHYSICS
you want h such that (assuming g=10 m/s^2) mgh = 1.2 mv^2 (10)(10)(h) = (1/2)(10)(10^2) h = 5m
January 30, 2016

Math
the integer dimensions must be factors of 12. So, 1x12 2x6 3x4 You worked out the combinations for a perimeter of 12. Using the above dimensions, now you can work out the possible perimeters
January 30, 2016

Math
A is ok. So, 120 mi/hr * 1/20 hr = 6 mi it would be nice had you shown your work...
January 30, 2016

math- HELP!
The F.S. tells you how many pairs there will be after n months. The sequence is 1, 1, 2, 3, 5, 8, 13, 21, 34, ... So, what is the 7th term? the 12th?
January 30, 2016

math- HELP!
so, did you actually read about the Fibonacci sequence?
January 30, 2016

physics2048
just think of the equations of motion. You want the heights to be the same, so 0 + 43.5t - g/2 t^2 = 15.4 - g/2 t^2 The actual value of g does not matter, since both balls are affected by it. So, you wind up with 43.5t = 15.4 see the heights at http://www.wolframalpha.com/...
January 30, 2016

information technology
read name, offence points = findpoints(offence) p = addpoints(name,points) suspension = (p>19):24?(p>13):12?(p>9):6:0 if suspension > 0 then   addsuspension(name,suspension)   display name,p,suspension end if
January 30, 2016

PHYSICS
?? act of fissure ??
January 30, 2016

math
man is half as high, so shadow is half as long.
January 30, 2016

math
P/20 = 3/4, so P=15 (15+5)/(20+5) = 20/25 = 4/5
January 30, 2016

COMPUTERS
PARAMETER (PI = 3.141592653589793) A = 2*PI*2**2 some dialects of FORTRAN define constants differently.
January 30, 2016

trigonometry
this particular sec/tan example falls out nicely: 1/(secx - tanx) = secx + tanx 1 = (secx+tanx)(secx-tanx) 1 = sec^2(x) - tan^2(x) one of the fundamental identities, arising immediately from sin^2 + cos^2 = 1 by dividing by cos^2
January 30, 2016

Physics
well, 50keV = 8.01 x 10^-8 ergs
January 30, 2016

math
well, a layer of water 1cm deep will have volume 49π cm^3. The volume of the cubes is 154 cm^3 That should tell you how to figure the depth of water occupied by the cubes.
January 30, 2016

math
c+(c+13)=27
January 30, 2016

Math
c'mon, guy - use what you know abot APs: (a+2d)+(a+6d) = 12 (a+2d)(a+6d) = 32 Now just solve for a and d, then you want a+8d. Hint: 4*8 = 32
January 30, 2016

Quick calc question
That would be f'(g(2x))g'(2x)(2x)' = f'(g(2))g'(2)(2) = f'(4)g'(2)(2) = 2*4*2 = 16
January 30, 2016

Quick calc question
why all the wordy mumbo jumbo? Ever heard of math symbols? f(x) = (1-x)/(1+x) g(x) = x/(1+x) f(g) = (1-g)/(1+g) = (1-(x/(1+x)))/(1+(x/(1+x))) = 1/(2x+1) the domain excludes x = -1, since g is not defined there. It also exludes x = -1/2, as shown by the final form of the fraction.
January 30, 2016

analytic geometry
distance extremes are at the ends of the semi-axes. You know that a=93, and c/a = 1/60. And, b^c+c^2=a^2. Hard to figure just what you are after with the ships, but apparently you want the angle ACB. Angle CAB is arctan(120/80)+10° To find the distance CB, use the law of ...
January 30, 2016

analytic geometry
The circle is (x-2)^2 + (y-1)^2 = 25 The shortest distance is along the line from the center (2,1) to (10,7). So, find the distance between those two points, and subtract 5, the radius of the circle. For the longest distance add 5, to the opposite end of the diameter. The ...
January 29, 2016

Math
-1/2 0 -3.14
January 29, 2016

Math
3000/(12.5*60) = 4 cents/min now you can answer the questions.
January 29, 2016

Geometry
the rectangle could be long and skinny: 1 x 2300 or approximately square: 46 x 50 Or, if you do not insist on integer dimensions, pick any width (w) you like, and the length is 2300/w.
January 29, 2016

Math (help please)
if the polygon has six sides, it is a hexagon.
January 29, 2016

MATHS
2(10+x) = 37+x
January 29, 2016

math
looks ok to me.
January 29, 2016

Math
well, that's obviously 12i^2 = -12
January 29, 2016

Music
seems to me that "drums" is the only member of the rhythm section. the others are strings or winds.
January 29, 2016

Geometry
multiply by 15 to get rid of those pesky fractions: x/3 = x + 2/5 5x = 15x + 6 10x = -6 x = -3/5 or, x/3 = (x+2)/5 5x = 3(x+2) 5x = 3x+6 2x = 6 x = 3
January 29, 2016

Calculus
as written, -y - xy' = 3y^2 y' (3y^2+x)y' = -y y' = -y/(3y^2+x)
January 29, 2016

physics
well, the resultant C = A+B = 5i-j+k |C| = √27 so, the unit vector is C/√27
January 29, 2016

math
90-x = (180-x)/5 - 10 now just solve for x.
January 29, 2016

Math
30 = 3*10 The 3-letter pattern repeats 10 times. so, Z
January 29, 2016

maths
sphere: v = 4/3 pi r^3 = 500pi/3 = 524 cm^3 The diameter of the sphere is equal to the depth of the water, so it will be completely submerged as the water level rises.
January 29, 2016

Trig
85 is correct 5 degrees from the vertical.
January 29, 2016

physics
since v = √(2as) v for a 1m fall is √19.2 v for a .81m bounce is √(.81*19.2) = .9√19.2 so, the c.r is 0.9 it's just the √ of the bounce-height ratio.
January 29, 2016

calc 1
do you mean (√(1+t)-√(1-t))/t ? That is indeed 0/0 "rationalizing" the numerator, we have (√(1+t)-√(1-t))(√(1+t)+√(1-t)) -------------------------------- t (√(1+t)+√(1-t)) (1+t)-(1-t) ---------------- t (√(1+t)+&#...
January 29, 2016

math
nope. 180 inches = 15 feet, not 15 yards. So, since 1 yd = 3 ft, now you can figure the yards.
January 29, 2016

Limits calc 1
nope. remember your Algebra I. (a^3+b^3) = (a+b)(a^2-ab+b^2)
January 29, 2016

Math
solve just like an equation: -15x+3 >= -3(4x-7) -15x+3 >= -12x+21 -18 >= 3x -6 >= x
January 29, 2016

math
1/x + 1/y = 1/2 I cannot parse the second sentence.
January 29, 2016

Math
well, did you plug in the values? 2(1.5)+5(1) = 3+5 = 8 6(1.5)+1 = 9+1 = 10 so, yes, that is the solution. Learn to check your answers after you figure them out.
January 29, 2016

Math plz...
no idea what you mean with -x+3, but the table has the rule y = 40-5x
January 29, 2016

Math
I assume you meant (2x-10)/5 = 3/4 4(2x-10) = 5(3) 8x-40 = 15 8x = 55 x = 55/8
January 29, 2016

calc 1
horizontal line at y=3 for 0<=x<=8 then horizontal line at y=22
January 28, 2016

chemistry
I think there is more to this problem than just an equation. Presumably, given enough TNT, you could produce as much water as you want. Though I suspect water production is not generally the purpose of the reaction ...
January 28, 2016

Purdue Trig
sounds like spherical trig to me.
January 28, 2016

math
geez, give it a rest already, willya? 10^3 * 26^2
January 28, 2016

geometry
clearly, when the longest side is the sum of the other two sides, the triangle has flattened into a line. So, 17-x = 8-x + 15-x 17-x = 23-2x x = 6 cutting off 6" leaves the lengths of 2,9,11, a flat triangle.
January 28, 2016

Math
Starting with $10, I bought 3 candy bars at 75 cents each, and 2 sodas at 50 cents each. How much money was left after the purchases?
January 28, 2016

Math
p=3s s=2m p-(x+y) = s+x p-(x+y) = m+y If p gives away 1/2 of his eggs, 1/6 to s and 1/3 to m, then Pablo has p/2 Sofia has p/3 + p/6 = p/2 Mia has p/6 + p/3 = p/2
January 28, 2016

Math Help
well, we are told that v(t) is the velocity at time t. Looks like B to me.
January 28, 2016

Help Math
exatamente correto de nada
January 28, 2016

math
37/1 -16/5 92/10 = 46/5 -23/100
January 28, 2016

Algebra
If there were x of each to start, then x = 4(x-66)
January 28, 2016

writing equations-Math
20(x-2) = 60 60/(x-2) = 20
January 28, 2016

triggggg help
well, tan = sin/cos, right? Also, 67.5° = 3pi/8 = tan(1/2 * 3pi/4) so you can use the half-angle formula tan(x/2) = sinx/(1+cosx) tan 3pi/8 = (1/√2)/(1-1/√2) = (1/√2) / (√2-1)/√2 = 1/(√2-1) = √2+1 or, √((2+√2)/(2-√...
January 28, 2016

Calculus
(√(6-x)-2)/(√(10-x)-3) (√(6-x)-2)(√(10-x)+3) ----------------------- (√(10-x)-3)(√(10-x)+3) (√(6-x)-2)(√(10-x)+3) ---------------------- 10-x-9 as x->1, that is (6√5 - 12)/±0 undefined
January 28, 2016

Tips
Once you have submitted your question, the screen will show a line like Your question, Tips, was successfully posted Click on the word Tips and your posting will open up again for your review. Proofread it and watch for typos, formatting, font problems, etc. Make sure it is ...
January 28, 2016

Tips
See tips below.
January 28, 2016

Calculus
http://www.jiskha.com/display.cgi?id=1453991598
January 28, 2016

Math
1/2 = 2^-1 32 = 2^5, so (2^-1)^(2-x) = (2^5)^(x+1) 2^(-1(2-x)) = 2^(5(x+1)) -2+x = 5x+5 4x = -7 x = -7/4
January 28, 2016

intermediate algebra
since time = distance/speed, 186/(24+x) = 102/(24-x)
January 28, 2016

Math
Draw a diagram. The line from the satellite and a city is tangent to the radius from the center of the earth. If that radius is r, then the angle θ subtended by the satellite and one city is θ = 1125/r So, if the satellite is h mi high, r/(r+h) = cosθ h = r/cos...
January 28, 2016

Math
sorry - ain't so. Check for typos However, cot(sec^-1(A)) = √(A^2-1) cot^2(sec^-1(A)) = A^2-1 I think I can see how the question was mangled. Can you?
January 28, 2016

math
take a look at the 2nd related question below.
January 28, 2016

Calculus
since p(t) is the population given time, p^-1(t) is the time needed to attain a certain population. p=7500/(1+749e^-0.15t) 1+749e^-0.15t = 7500/p 749e^-0.15t = 7500/p - 1 e^-0.15t = (7500/p - 1)/749 -0.15t = ln((7500/p - 1)/749) t = -20/3 ln((7500/p - 1)/749) or t = -20/3 ln((...
January 28, 2016

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