Wednesday

February 10, 2016
Total # Posts: 37,530

**pre-calc college**

No idea. What's x? 4 uncut lengths will for a square, the quadrilateral which has the largest area for a given perimeter.
*January 31, 2016*

**Trigonometry**

oh, come on. You want QII and QIV. So, using π/4 as a reference angle, that gives you for your first solution, 3π/4 Now the period of cot(x) is π, so add/subtract π over and over till you arrive at -2π or 2π 3π/4+π/4 = 7π/4 3π/...
*January 31, 2016*

**Trigonometry**

cot π/4 = 1 now, where is cot(x) negative? Use π/4 as your reference angle.
*January 31, 2016*

**physics**

at t=0 we have 12.5 sin(0+x) = -0.0325 x = -0.149 So, x(t) = 12.5 sin(3πt - 0.149) = 12.5 sin(3π(t-0.0159)) So, the phase is -0.0159
*January 31, 2016*

**Math**

assuming sunset at 6 pm, the angle of elevation of the sun at 3 pm is 45°, so the shadow is as long as the tree's height.
*January 31, 2016*

**surface area and volume**

Hmmm. I interpret the problem to be that the cones have the same diameter. Hence, the same base radius. Since the curved surface area is πrs, if r is constant, then the area is proportional to s, so it is also in the ratio 5:4.
*January 31, 2016*

**math**

I have no idea how to read your text. Is x a variable or a multiplication operator? Online we usually use * for multiplication. -- is not an operator I know. You would do well to read some other math postings to see how expressions are written. Yours is gibberish.
*January 31, 2016*

**math**

why not use real math? (x-6)/3 - (x-27)/9 = 3 x=9 or, since you are careless with parentheses, (x-6)/(3-x) - 27/9 = 3 x = 24/7 I suspect the first one was your intention. Use parentheses to make things clear. And lose all those useless words! This is math!
*January 31, 2016*

**Math**

Assuming you want 384 pieces, each is 1 inch long. Now take a hike.
*January 31, 2016*

**Math**

don't hold your breath. Until you say how many parts you want, there's no way to determine how long each must be. Consider the factors of 32. Pick one.
*January 31, 2016*

**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*

**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*