Thursday

February 11, 2016
Total # Posts: 37,579

**Math**

The total points are not 13, but 35+10 = 45. So, using x,y,z for the scoring plays in the same order as described above, 6x+y+3z = 45 x = y x = 6z You certainly don't need elimination for this, since the substitutions are so easy.
*February 2, 2016*

**algebra**

since v = Bh, you have 264 = 48h ...
*February 1, 2016*

**Calculus**

First off, the equation should be (f(x+h)-f(x-h))/(2h) if f(x) = a(x-b)^2+c, then f(x+h) = a(x-b+h)^2+c f(x-h) = a(x-b-h)^2+c f(x+h)-f(x-h) = a((x-b +h)^2 - (a-b -h)^2 = 4ah(x-b) divide that by 2h and you have 2a(x-b) Now, f'(x) = 2a(x-b) ta-daa
*February 1, 2016*

**Precal**

enter your coefficients here: http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
*February 1, 2016*

**math**

well, if you got 100% on all your tests, that would account for 70% of your grade. So, you'd then need at least 33.3% on the homework. But, if you scored 100% on all the homework, that would account for 30% of your grade, so you'd need 71.43% on the tests. So, the ...
*February 1, 2016*

**More math**

all correct. good work.
*February 1, 2016*

**Math**

if there are c chickens, then there are 40-c cows. So, adding up the legs, 2c + 4(40-c) = 100
*February 1, 2016*

**Do I have enough time**

Don't forget that you will have to spend a half hour correcting your spelling and grammar, too!
*February 1, 2016*

**Math**

If I read your language correctly, there is a 5m border around the field. So, if the dimensions of the whole area is 130x85, then the field is 120x75.
*February 1, 2016*

**Math**

as usual, k∘d = k(d) = √(d^2+100) = √((35t)^2+100) assuming t is in hours.
*February 1, 2016*

**math**

NO! Read we wrote!!! The sides are 9 over √2
*February 1, 2016*

**math**

If the diagonal is d=x√2, then x = d/√2 you did d*√2 instead.
*February 1, 2016*

**Biology**

Wine is made by mixing yeast with grapes and allowing the yeast cells to undergo fermentation. Sparkling wine is a type of wine that contains high levels of dissolved carbon dioxide. What is the source of the carbon atoms in the carbon dioxide found in sparkling wine? ethanol ...
*February 1, 2016*

**Biology**

I'm sorry I meant c
*February 1, 2016*

**Biology**

What would most likely happen to cells placed in fresh water? a- water would flow out because they are hypotonic to the external environment b- water would flow into them because they are hypotonic to the external environment c- water would flow out of them because they are ...
*February 1, 2016*

**math**

assuming you want integer values, just find the factors of 389 Hmm. 389 is a prime number. So, just pick any value (x) for the width and the length is 389/x. I suspect a typo.
*February 1, 2016*

**chemistry**

HCl + NaHCO3 = NaCl + H2O + CO2
*February 1, 2016*

**Math**

That is correct.
*February 1, 2016*

**Geometry**

4(1)-4(-1)+2 = 4+4+2 = 10 ??
*February 1, 2016*

**Geometry**

I don't see any choices which work. I suspect a typo.
*February 1, 2016*

**Geometry**

That does not work: 2(1)-2(-1)+2 = 6 Better try again.
*February 1, 2016*

**Math**

seems so.
*February 1, 2016*

**Science**

since F = 9.5 N/m, you want W = ∫[0,0.06] 9.5 x dx = 0.0171Nm = 0.0171J see http://www.intmath.com/applications-integration/7-work-variable-force.php
*February 1, 2016*

**Math**

it is only one of them.
*February 1, 2016*

**Math**

see previous post.
*February 1, 2016*

**Math**

yes.
*February 1, 2016*

**Math**

yes
*February 1, 2016*

**algebra**

just substitute 8 for each of the t's and add up teh numbers.
*February 1, 2016*

**Geometry**

The sides are 2x,3x,4x Add them up and you have 9x=45 ...
*February 1, 2016*

**Geometry**

The angles are 3x,4x,5x Sum them up and you have 12x=180 Now find x, and thus the angles.
*February 1, 2016*

**Math**

Recall that for a cubic polynomial ax^3+bx^2+cx+d, the sum of the roots is -b/a. The sum of the roots is -3-1+5 = 1 So, only A is the answer.
*February 1, 2016*

**Science**

looks good to me.
*February 1, 2016*

**Math**

Find functions of f•g, g•f, and their domains. f (x)=sqrtx-1, g (x)=x^2 Thank you very much
*February 1, 2016*

**maths**

9/2 (2a+8d) = 216 (a+2d)/a = (1+6d)/(a+2d) One choice is 24, 24, 24, ... Probably not what you want. So, let's try 8, 12, 16, ...
*February 1, 2016*

**Pre-Algibra**

pi r^2 h = v 3.14 * r^2 * 14 = 718.4 Now just find r.
*February 1, 2016*

**Math**

just scramble DEF in the same order as ABC. clearly the 1st and last choices are wrong...
*February 1, 2016*

**math**

If Z is the vertex, then the other two angles are (180-25)/2 If Z is one of the base angles, then other is also 25, and the vertex angle is 130
*February 1, 2016*

**math**

funny thing -- it looks like every other sine wave... http://www.wolframalpha.com/input/?i=sin%281*pi*1000t%29+%2B2 No idea what v(t) has to do with it, though.
*February 1, 2016*

**Math**

you could be right.
*February 1, 2016*

**Math**

4 bagels, 5 people 4/5 bagel/person
*February 1, 2016*

**Math**

statement: p => q converse: q => p contrapositive: -q => ~p inverse: ~p => ~q
*February 1, 2016*

**Math**

that would be true, but alas, 150° is not an acute angle. and that's obtuse, not abuse...
*February 1, 2016*

**Physics**

heavy, man...
*February 1, 2016*

**math**

your given solutions are correct. As for the last one, x+y=100, so x(100-x)=60 ...
*February 1, 2016*

**math**

ad-bc=0 ad = bc a/c = b/d
*February 1, 2016*

**Math**

for x ft^2, the cost will be equal when 79.50 + 1.00x = 0.00 + 2.50x
*February 1, 2016*

**Math**

you know that √n has domain n>=0. So, your domain is all x such that 7-3x >= 0 And you [should] know that the range of a^u is (0,∞).
*January 31, 2016*

**Physics**

looks good, except it should be (100-10)/20
*January 31, 2016*

**Math**

1/3 + 5/6 = 2/6 + 5/6 = 7/6 = 1 1/6 No idea what the rest of the stuff is saying.
*January 31, 2016*

**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*