Monday

September 26, 2016
Total # Posts: 44,051

**physics**

s = 1/2 at^2, so 1/2 a * 4.54^2 = 8.1 Now use that to figure how far it goes in the next second. v = a*t s = v*1 + 1/2 a * 1^2

*September 1, 2016*

**science help pls pls**

google planetary orbit period You will find lots of explanations, with the formula. I cannot believe that this question was asked of you without providing the formula, either in class or in the text. I also cannot believe that you expect someone to provide it for you.

*September 1, 2016*

**science help pls pls**

Just plug these numbers into your formula for orbital periods and subtract.

*September 1, 2016*

**math**

first place in standard form: x^2/8 + y^2/3 = 1 Since a^2 = 8 is greater than b^2 = 3, the major axis is horizontal. So, we have a^2 = 8 b^2 = 3 c^2 = a^2-b^2 = 5 Now just read off the info you want: center: (0,0) foci: (±c,0) vertices: (±a,0)

*September 1, 2016*

**Math**

consider 8^12 = 8*8*8...*8 12 times 8*9 = 8*8*8...*8 9 times nine of those factors cancel out, leaving 3 in the top, or 8^3 This is why x^m / x^n = x^(m-n) since n of the factors cancel out when reducing the fraction.

*September 1, 2016*

**Discrete Math Proof Exercise**

first, you need to show that only even+odd = odd even+even = 2m+2n = 2(m+n) = even odd+odd = 2m+1 + 2n+1 = 2m+2n+2 = even even+odd = 2m + 2n+1 = 2(m+n)+1 is odd so, if 3n^2+5 is odd, 3n^2 is even Since 3 is odd, n^2 must be even, which means that n is even, since odd*odd = (2m...

*September 1, 2016*

**Calculus**

Let M = ∫ e^(2x) cos3x dx u = cos3x du = -3sin3x dx dv = e^(2x) dx v = 1/2 e^(2x) M = uv - ∫v du M = 1/2 e^(2x) cos3x + (3/2)∫e^(2x) sin3x dx Now consider ∫e^(2x) sin3x dx u = sin3x du = 3cos3x dx dv = e^(2x) dx v = 1/2 e^(2x) ∫e^(2x) sin3x dx = 1...

*September 1, 2016*

**MATH**

3/5 * 3/4 = 9/20 so, if the full amount is x, then 9/20 x = 360 x = 360 * 20/9 5/8 of x is thus (5/8)(360)(20/9) = ?

*September 1, 2016*

**Math**

slope = 4, so the point-slope form of a line is y+1 = 4(x+5) massage that into whichever other form you desire

*September 1, 2016*

**Mathematics**

since the distance is the same, rate*time is constant. So, you want m minutes where 36m = 15*60

*September 1, 2016*

**algebra,geography**

see related questions below.

*September 1, 2016*

**Math asap**

and you are wrong. -3 < 2

*September 1, 2016*

**Math asap**

see related questions below. I know I've seen this answered at least once for you.

*September 1, 2016*

**Math**

still 3, right?

*September 1, 2016*

**Math**

15500

*September 1, 2016*

**Geometry**

no idea what you are saying: M 6 + 16 + z -1 and 14 ???!?!?!?

*September 1, 2016*

**Geometry**

wow, use language much? As I strain mightily to make sense of what you wrote, I get The midpoint of UV is (5,-11), and the coordinates of U are (3,5). well, since the midpoint M is halfway from U to V, and that distance is (2,-16), add those values to M to get all the way from...

*September 1, 2016*

**Math**

It takes 3 points to form a triangle, so there are 6C3 ways to choose them.

*September 1, 2016*

**Geometry - mangled**

fix the typos and repost, ok? It's basically gibberish as it stands.

*September 1, 2016*

**MATH**

nope. -3 < 2

*September 1, 2016*

**MATH**

what is 98?

*September 1, 2016*

**Physics**

convert each vector to x-y values add the x and the y values convert back to directional form

*September 1, 2016*

**math**

45km/hr * 1hr/60min * 1rev/(1.5π m) * 1000m/km = 159rev/min

*September 1, 2016*

**Math**

c(x) = 2*5x + 2*4x = 18x

*September 1, 2016*

**Math**

30 trips * 2*15 mi/trip * 1gal/28mi * $4/gal = $128.57

*September 1, 2016*

**Technology**

correct

*September 1, 2016*

**College Algebra - incomplete**

sorry - one equation in three variables has no unique solution by any method.

*September 1, 2016*

**Math**

consider how much of the job gets done in one hour. Mary does 1/2 Gina does 1/3 So, ever hour, 1/2 + 1/3 = 5/6 of the job gets done. If 5/6 gets done in one hour, the whole job takes 6/5 hours. 1/2 + 1/3 = 1/x For further discussions, I refer you to (a) your class text (b) ...

*September 1, 2016*

**physics**

If you have two vectors u and v, resultant is w = u+v equilibrant is w such that u+v+w = 0. That is, w = -(u+v)

*September 1, 2016*

**Maths**

let's call the roots a and b, just for ease of typing. f(x) = x^2-6x+k recall the sum and product of the roots: a+b = 6 ab = k Now, we have a^2 + b^2 = 40 but, a^2 + b^2 = (a+b)^2 - 2ab So, 36 - 2k = 40

*September 1, 2016*

**Math question for Steve**

yes. just figure the calls each day and keep adding them up. The table looked pretty clear to me. When the total exceeds 300, that's the day the 300th call was received.

*September 1, 2016*

**Math**

the slopes must be the same, so (8-1)/(-2-a) = (1-5)/(a+2-12) -7/(a+2) = -4/(a-10) 7(a-10) = 4(a+2) 7a-70 = 4a+8 3a = 78 a = 26

*September 1, 2016*

**Math problem soving**

Huh? Surely you can see that on day 6 the 300th call came in.

*August 31, 2016*

**Differentiation**

Rats. How about y x^(y-1) y' + lnx x^y + x y^(x-1) y' + lny y^x = 0 (y x^(y-1) + x y^(x-1))y' = -lnx x^y - lny y^x Note that x^(y-1) = x^y/x, so (y/x x^y + x/y y^x)y' = -lnx x^y - lny y^x ...

*August 31, 2016*

**Differentiation**

To differentiate u^v, where u and v are functions of x, use a combination of the easy formulas you already know: y = u^n y' = n u^(n-1) u' y = a^v y' = lna a^v v' x^y + y^x = 1 x^(y-1) y' + lnx x^y + y^(x-1) y' + lny y^x = 0 (x^(y-1) + y^(x-1))y'...

*August 31, 2016*

**Math**

The receiver is 10 yd downfield and 53 1/3 - 25 - 5 = 23 1/3 yds to the right. So, the distance is clearly √(10^2 + (70/3)^2) yds QB: (25,25) Rcvr: (35,48 1/3) So, take their averages to find the midpoint.

*August 31, 2016*

**Precalculus**

V(t) = 2600 - 145(t-13)

*August 31, 2016*

**9th grade algebra**

don't be scared by that x. It's juts a denominator. To get rid of it, multiply both sides by x. Now, to find x when h = -2, just do what you did: 12/x = -2 now just multiply by x: 12 = -2x x = -6

*August 31, 2016*

**Math**

x + 2(x+2) = x+4 + 20 Now just solve for x, the smallest

*August 31, 2016*

**Math**

(d/7) weeks, so (d/7)/4 = d/28 months

*August 31, 2016*

**math**

how do you drop by -5.7° Maybe you mean either it dropped by 5.7° or, it changed by -5.7° In that case, after 3.5 hours, the change is clearly -5.7 * 3.5° So, add that to the starting 23°, and what do you get?

*August 31, 2016*

**Math**

Or, it occurs to me that maybe you have garbled the question, and it should read $75 per month plus $0.30 per minute after the first thousand minutes In that case, it's just y = 75.00 for 0 <= x <= 1000 y = 75.00 + 0.30(x-1000) for x > 1000

*August 31, 2016*

**Math**

there is a flat fee of 75.00, so start with that: y = 75.00 Now, add .30 for each minute. For x minutes, that is .30x, so y = 75.00 + 0.30x No information is given on what happens after the first 1000 minutes, so all we can do is restrict the domain to what we know: y = 75.00...

*August 31, 2016*

**Pre-Calulus**

15000/15 - 15000/18 = 166.67 or, since the old car used 1000 gallons, the new car, with 20% (6/5) better mileage uses 5/6 as much gas, saving 1/6 of 1000 = 166.67 gallons.

*August 31, 2016*

**Algebra**

yes, just as with normal fractions 2/3 + 4/7 has an lcd of 4*7 3/4 + 1/6 has an lcd of 12 instead of 24, since 2 is a common factor of both 4 and 6. LCD(m,n) = mn/GCF(mn)

*August 31, 2016*

**Algebra**

x^2-9 = (x+3)(x-3) so that is the lcd 1/(x-3) + 1/(x+3) = 10/(x^2-9) multiply through by x^2-9 and you have (x+3) + (x-3) = 10 2x = 10 x = 5 For #2 if you mean 5/(2x) - 5/(3(x+5)) = (5/x) the lcd is 2x(3(x+5)) so 5(3(x+5) - 5(2x) = 5(2)(3(x+5)) 15x+75 - 10x = 30x+150 If I got ...

*August 31, 2016*

**algebra**

f^-1(9/x) = 9/x since f^-1(f(x)) = 9/(f(x)) = 9/(9/x) = x swap variables and solve for y: x = (2y+1)/(3-2y) x(3-2y) = 2y+1 3x-2xy = 2y+1 3x-1 = 2xy+2y 3x-1 = y(2x+2) y = (3x-1)/(2x+2)

*August 31, 2016*

**Algebra**

you only need an lcd if you are adding fractions with unlike denominators. Multiplication and division just work on the tops and bottoms separately.

*August 31, 2016*

**Algebra**

(5/8)/(-2/3) = (5/8)(-3/2) = -15/16 (x^-1+y^-1)/(x+y) = (1/x + 1/y)/(x+y) = ((x+y)/(xy))/(x+y) = 1/(xy)

*August 31, 2016*

**algebra**

s/3600

*August 31, 2016*

**Math**

The bill for x + 1/4 miles is .75 + .35x <= 7.40

*August 31, 2016*

**Math**

105 cannot be their least common factor, as it has its own smaller factors. Though I think the question has been garbled, since I cannot understand "two pairs of numbers of 105"

*August 31, 2016*

**biology**

surely you know what "complex" means and also the molecular level, as opposed to the more large-scale aspects. You know about molecules, right? So, given those ideas, and a little thought (and maybe some help from google) what do you think?

*August 31, 2016*

**linear algebra - can't grok**

your economy of typing (laziness?) makes your posting almost unintelligible. We don't mind helping you find the answers, but don't ask us to figure out the questions as well, ok? and what the heck is a signal lac?

*August 31, 2016*

**math**

24 students makes 12 pairs. There are 3 pairs to go. So, how many magnets is that?

*August 31, 2016*

**Math**

.30x = 90

*August 31, 2016*

**geometry**

how are the angles arranged? That is, what is the order of D,F,G,H around point E? Are there any right angles or straight angles in the picture?

*August 31, 2016*

**math**

yes

*August 31, 2016*

**Math**

7x1=7 7x2=14

*August 31, 2016*

**Biology **

Explain the following statement: "life is complex on a molecular level. How is your environment different from the biosphere?

*August 31, 2016*

**Math**

multiply all the powers by 4. 2^4 = 16

*August 31, 2016*

**Math**

two points cannot intersect B is also false, since the sign of the y-values are not both positive. This whole question appears bogus.

*August 31, 2016*

**Math**

If they lost x, then x + 2x+15 = 78

*August 31, 2016*

**Math**

(8/5) * 40

*August 31, 2016*

**Algebra 1**

5 more than x: x+5 5 more than (half Karen's salary): (k/2)+5 Your answer is half of (5 more than Karen's salary).

*August 31, 2016*

**Algebra 1**

correct

*August 31, 2016*

**Algebra help**

I like D!

*August 31, 2016*

**Algebra help**

oh, and speed is not measured in feet. Distance is measured in feet. Speed is measured in feet per second miles per hour or something else like that

*August 31, 2016*

**Algebra help**

I think so. speed depends on time and distance. None of the answers really is complete, but they all say something depends on something else. For a given distance, speed depends on the time it takes to travel that distance. So, if you want to determine Andy's speed, ...

*August 31, 2016*

**Algebra help**

speed = distance/time

*August 31, 2016*

**Math**

Draw a number line. You will see that -5 is to the right of -8. So, -5 > -8 and yes, -6 < |-8| = 8

*August 31, 2016*

**Mathematics**

yep

*August 31, 2016*

**Math**

Draw any convex polygon of n sides. From any vertex, there are n-1 other vertices to reach. But two of those are adjacent, so a joining line is just a side. That leaves n-3 other vertices. Joining to them will form diagonals.

*August 31, 2016*

**math work**

as long as we're using determinants, u•v×w = |9 -7 -3| |-6 1 -5| |2 8 -9|

*August 31, 2016*

**math work**

see related questions below

*August 31, 2016*

**Math**

maybe it's 7/12, since 1/3 + 1/4 = 7/12

*August 31, 2016*

**Science**

v^2 = 2as, so 25 = 10a a = 2.5 m/s^2 F = ma = 1.25N

*August 31, 2016*

**math**

9 1/4 - 15 2/6 = -(15 4/12 - 9 3/12) = -6 1/12

*August 31, 2016*

**math**

5 4/12 - 3/12 = 5 1/12

*August 31, 2016*

**math**

well, the chance that both are girls is 8/14 * 7/13

*August 31, 2016*

**Math**

rice: 11/18 tomatoes: 3/7 * 7/18 = 1/6 spinach: 1/4 * 2/9 = 1/18 1 - 11/18 - 3/18 - 1/18 = 3/18 so, 1/6 of the field is yams

*August 31, 2016*

**math**

88/2 = 44 44/2 = 22 22/2 = 11 2^3 * 11 = 88

*August 31, 2016*

**Math**

.20 * .65 * 25 = ?

*August 31, 2016*

**Pre-calculus**

see related questions below

*August 31, 2016*

**math**

why the decimals? We're practicing mixed numbers here 7 1/2 - 5 3/4 = 6 6/4 - 5 3/4 = 1 3/4

*August 31, 2016*

**math**

Take a look at the following article, and see what you can come up with: https://betterexplained.com/articles/navigate-a-grid-using-combinations-and-permutations/

*August 31, 2016*

**Geometry**

x^2+y^2+3x-8y+16=0 is the circle (x + 3/2)^2 + (y-4)^2 = 9/4 So, the center of the circle is at (-3/2,4) The distance to the line 4x+3y-12=0 is thus |4(-3/2) + 3(4) - 12|/√(4^2+3^2) = 6/5 So, the desired circle is (x + 3/2)^2 + (y-4)^2 = 36/25

*August 31, 2016*

**Geometry**

find the distance from the center of the circle to the line. Use that for the radius of the circle.

*August 31, 2016*

**maths**

9/12 = 75%

*August 31, 2016*

**maths**

Simon's distance: 6x Jade's distance: 11y 11*6 + 6x = 114

*August 31, 2016*

**algebra**

Start with the url below and fix your typos till you get one of your choices: http://www.wolframalpha.com/input/?i=solve+1%2F3x+%2B+3%2F4+y+-+2%2F3+z+%3D+-8,+x+%2B+1%2F2+y+-+1%2F3z+%3D+18,+1%2F6+x+-+1%2F8+y+-+z+%3D+-24

*August 31, 2016*

**math**

add the two equations and y drops out: 2x^2-22x = -48 x^2-11x+24 = 0 (x-3)(x-8) = 0 Now just find the y for each x.

*August 31, 2016*

**math**

If all you can do is multiply and divide, I don't see how it can be done. 5 and 7 are primes, and there is no way to cancel them as factors

*August 31, 2016*

**physic**

speed (m/s) = wavelength (m) * frequency (1/s) v = λf so, for a given frequency, the velocity is directly proportional to the wavelength. Get v in air, and then you can figure v in glass.

*August 31, 2016*

**physics**

T = kML

*August 31, 2016*

**math**

(a+b+c)^3 = a^3 + 3a^2b + 3a^2c + 3ab^2 + 6abc + 3ac^2 + b^3 + 3b^2c + 3bc^2 + c^3 so, (x^2+x+1)^3 expands as x^6 + 3x^5 + 3x^4 + 3x^4 + 6x^3 + 3x^2 + x^3 + 3x^2 + 3x + 1 which is what was above

*August 31, 2016*

**Algebra**

the first train is 40 miles ahead when the 2nd train starts. The 2nd train is going 10 mi/hr faster, so how long do you think it will take to cover the extra 40 miles?

*August 31, 2016*

**Math**

16/(26+19+21+26+32)

*August 31, 2016*

**Algebra**

google is your friend.

*August 31, 2016*

**Algebra 2**

all polynomials have a domain of all real numbers. Any straight line which is not a simple y = k horizontal line also has a range of all real numbers. To see this, just draw any line. It extends forever both left and right, and up and down. (unless ut is horizontal)

*August 31, 2016*