Tuesday

February 21, 2017
Total # Posts: 48,680

**math**

x(t) = 9t^2/2 - t^3/2 v(t) = 9t - 3t^2/2 a(t) = -3t Now it should be easy to answer the questions.

*December 16, 2016*

**algebra**

300+5x = 700-6x love the duplication. :-(

*December 16, 2016*

**algebra**

t^0 = 1 negative exponents cause switch between top and bottom (4t)^2t^0/t^6v-8 = 16t^2 * v^8/t^6 = 16v^8/t^4 or 16 t^-4 v^8 p^-3/p^-2r^3 = 1/p^3 / (r^3/p^2) = p^2/(p^3r^3) = 1/(pr^3) or p^-1 r^-3

*December 16, 2016*

**geometry**

the one that's about 78.5/3.14

*December 16, 2016*

**Math (please help!!)**

the last one the clue is that a right angle is perpendicular hence, it belongs with perpendicular bisectors

*December 16, 2016*

**Algebra 2**

3.stretch: 3x^3 right: 3(x-4)^3 down: 3(x-4)^3 - 3

*December 16, 2016*

**math**

x^2 + 15^2 = 19^2

*December 16, 2016*

**math**

surely you can at least do part 1. ?

*December 16, 2016*

**Algebra**

x >= 2 1.75 + 0.55x <= 10.00

*December 16, 2016*

**harmonic progression**

again with this stuff? n ?k(k+1)(2k+1) k=1 = ?(2k^3+3k^2+k) = 2?k^2 + 3?k^2 + ?k Now just consult your reference for special sums of powers to get a 4th-degree polynomial for n.

*December 16, 2016*

**Math - Coordinate Geometry**

The slope of 2x-3y+3=0 is 2/3. The parallel line you want has a slope of 2/3 and passes through (6,-4) So, using the point-slope form of the line, y+4 = 2/3 (x-6)

*December 16, 2016*

**calculus**

y = arctan(x) tan(y) = x sec^2(y) y' = 1 y' = 1/sec^2(y) = 1/(1+tan^2(y)) = 1/(1+x^2)

*December 16, 2016*

**algebra**

(-x)^2 (-x)^5 = (-x)^7 = -x^7 (-3m^3)^2 = (-3)^2 (m^3)^2 = 9m^6 (x/y)^-3 = (y/x)^3 = y^3/x^3 or, (x/y)^-3 = x^-3 / y^-3 = x^-3 y^3

*December 15, 2016*

**Algebra**

x @ 2pts y @ 1pt x+y = 50 2x+1y = 87

*December 15, 2016*

**Algebra**

3x-500 = 840

*December 15, 2016*

**Pre geometry**

check your theorems on transversals of parallel lines. alternate/corresponding interior/exterior angles are equal adjacent angles are supplementary I suspect your answer is 132 degrees, but I have no diagram to consult.

*December 15, 2016*

**uchs**

so, I guess the width is 6+7t

*December 15, 2016*

**Math**

(5u)+(5u - 8/3) ----------------- 2 though I'm not sure how 8/3 fewer is possible.

*December 15, 2016*

**MATH 2**

147 is 1.4 std above the mean, so ...

*December 15, 2016*

**Math**

a+c = 163 11a+6c = 1578

*December 15, 2016*

**ST KYLINS**

My digits in the ones period are zeros. xxx,xxx,000 now what else do you know?

*December 15, 2016*

**calculus**

this should help http://www.jiskha.com/display.cgi?id=1481848543

*December 15, 2016*

**Maths**

I agree. Since the distance between the foci is only 2, there is no way that the condition can be met.

*December 15, 2016*

**Maths**

google is your friend. Try this to get going: https://people.richland.edu/james/lecture/m116/conics/hypdef.html

*December 15, 2016*

**Algebra II**

V = k/P, so VP = k, a constant so, you want V so that 2.2V = 20*16 By the way, L/cm^2 is not pressure. 1L = 1000cm^3, so L/cm^2 = cm Pressure is force/area, as in N/m^2 I've never heard of this L/cm^2 unit. But then, I'm not a physicist...

*December 15, 2016*

**Algebra**

h^2+27^2 = 38^2

*December 15, 2016*

**algebra**

9.6/3.2 * 10^(2-5) = 3.0 * 10^-3

*December 15, 2016*

**algebra**

2.5^4 * (10^-2)^4 = 39.0625 * 10^-8 = 3.90625 * 10^-7

*December 15, 2016*

**Math**

so the square must be 4x4 what do you mean when you say "all sides"? Only the sides, not the rows or columns, or diagonals? For 4 numbers to add to 25, either one or three of them must be odd. See what you can do with that.

*December 15, 2016*

**calc**

e^(x^2-x+a) if x < 1 as x->1-, f(x) -> e^a (4^x-x^2)) if 1<x<2 as x->1+, f(x) -> 4^1-1 = 3 as x->2-, f(x) -> 4^2-2^2 = 12 6In(x-b) if x>2 as x->2-, f(x) -> 6ln(2-b) so, we need e^a = 3 a = ln3 6ln(2-b) = 12 ln(2-b)=2 2-b = e^2 b = 2-e^2 But ...

*December 15, 2016*

**Calc**

?(5-x) is defined for x<5 so, using x<1 works there lnx is defined for x>0 so, x>1 works there except where x=25 So, f(x) is defined and continuous on (-?,1)U(0)U(1,25)U(25,?)

*December 15, 2016*

**science**

none, if it's limestone

*December 15, 2016*

**algebra**

just move the decimal point. to the left for negative powers to the right for positive powers

*December 15, 2016*

**precalculus**

Nope. B First, show that P(1) is true. Then you assume C so you can prove D.

*December 15, 2016*

**precalculus**

Nope. A.

*December 15, 2016*

**precalculus**

yep

*December 15, 2016*

**Calc**

consider the case f'(x) = x

*December 15, 2016*

**precalculus**

since we're dealing with powers of 2, I'd pick B Besides, if k>1, (k+1) ? (k+k)

*December 15, 2016*

**precalculus**

correct, if you use a few parentheses: 3^(k+1) > (k+1)*2^(k+1)

*December 15, 2016*

**Maths**

Find the roots of the polynomial. Then find the slope at those points. y'=2-2x Then use the point-slope form to get the line equations. Do the same for the normals, with slope -1/y' Find the intersections, and then you can measure the triangle. Here's a start, ...

*December 15, 2016*

**Geometry**

So, how's that copy/paste working out?

*December 15, 2016*

**math**

so what? It was blazing hot at noon.

*December 15, 2016*

**Math**

If the dimensions are x,y,z, you need to find the minimum of 2xy+2xz+2yz using xyz=729 I think you will find that a cube does the job, just as a square minimizes the perimeter for a given area.

*December 15, 2016*

**Math**

b = 2c s = b-10 b+c+s = 100 Now just crank it out.

*December 15, 2016*

**Algebra**

Oh, right. C is indeed correct.

*December 15, 2016*

**Algebra**

if y varies directly with x, y=kx. So, y/x is constant. It is clear that this is not the case. Especially not y=10x. That would give the table 8|80 16|160 24|240 How ever did you arrive at that answer?

*December 15, 2016*

**precalculus**

I pick D. Then you have to add a term to both sides: 1+4+7+10 + + (3k-2)+(3(k+1)-2) = k/2 (3k-1) + (3(k+1)-2) and then show that k/2 (3k-1) + (3(k+1)-2) = (k+1)/2 (3(k+1)-1) watch the parentheses when working online. Things can be misread due to the lack of text formatting.

*December 15, 2016*

**Math**

32 days is 4 half-lives, so divide by 2^4 = 16

*December 15, 2016*

**Math**

seems legit to me. Though if they are in slope-intercept form, y is isolated, so substitution would work equally well.

*December 15, 2016*

**math**

reflect through x=3: (x,y)->(3-(x-3),y) = (6-x,y) reflect through y=x: (x,y)->(y,x) so, now just combine those two transformations: (x,y)->(6-x,y)->(y,6-x)

*December 15, 2016*

**Maths**

each gardener takes 3*90 = 270 minutes to do the job alone. So, since 15 = 270/18 It will take a total of 18 gardeners.

*December 15, 2016*

**Maths**

(a+b+c)/3 = 2d (a+b+c+d)/4 = 28 so, 6d + d = 4*28 ...

*December 15, 2016*

**Math**

No way to tell, since you give no information about e and F.

*December 15, 2016*

**Calculus**

f' = 3x^2+2ax+b Now just find a and b so that f' has factors (x-1)(x-5) Then you can determine the rest using f".

*December 15, 2016*

**Maths science his french**

use Snell's Law

*December 15, 2016*

**Math**

6(43-35) ...

*December 15, 2016*

**Math**

11x + 55 = 11(x+5)

*December 15, 2016*

**Math**

4*5 + 4*1/8 = 20 1/2

*December 15, 2016*

**Maths**

The diagonals are perpendicular, and bisect each other. Draw the diagram. Each triangle formed is a 3:4:5 right triangle.

*December 15, 2016*

**Math**

60 hot dogs per year? per month? per week?

*December 15, 2016*

**physics**

200/30 * 2pi rad/s

*December 15, 2016*

**Algebra**

x^2 + y^2 + 10x + 8y = 40 x^2+10x + y^2+8y = 40 x^2+10x+25 + y^2+8y+16 = 40+25+16 (x+5)^2 + (y+4)^2 = 81 That help?

*December 15, 2016*

**Math algebra**

well, you have the equation. Just plug in Ao = 1000 t = 50

*December 15, 2016*

**Math**

no idea. what fraction is paid?

*December 15, 2016*

**physics**

Consider that A+B and A-B are the diagonals of a parallelogram. When are the diagonals equal?

*December 15, 2016*

**physics**

4.9t^2 = 75 the 2nd part depends on the horizontal speed, which is constant.

*December 15, 2016*

**algebra 1**

bh/2 = 27 (h+3)h/2 = 27 ...

*December 15, 2016*

**Math**

3/4 (8u-12)

*December 14, 2016*

**math**

I predict it will be y = a cos(bx)

*December 14, 2016*

**Pre-calculus**

However, r = -5/(2cos? + sin?) is a line. r(2cos?+sin?) = -5 2x+y = -5 Now the intercept isn't so hard to find, eh?

*December 14, 2016*

**Math**

no way to tell. depends on the "steady rate"

*December 14, 2016*

**Algebra**

(a) after x pumps, we have sit(x) = 3 + 2x stand(x) = 3 * 1.2^x Now just use those functions to solve for the needed values.

*December 14, 2016*

**Science**

recall that F = ma

*December 14, 2016*

**math**

what's to justify? It has a steepness...

*December 14, 2016*

**Algebra**

clearly, at x = -2 and 1.

*December 14, 2016*

**Math**

11th term is a+10d that will make a difference.

*December 14, 2016*

**Math**

try putting things into standard form: (2x+6)(3x-1)=2 6x^2 + 16x - 6 = 2 6x^2 + 16x - 8 = 0 or 3x^2 + 8x - 4 = 0 Now just use the quadratic formula.

*December 14, 2016*

**algebra**

it already is. Just add the power of 10 3.000052 * 10^0 Now, if you mean that problem #3 was .000052, that is 5.2 * 10^-5

*December 14, 2016*

**Math**

why use 50 for the common denominator, when 10 works just as well? 13/5 + 29/10 = 26/10 + 29/10 = 55/10 Now subtract that total from the 11 hours (110/10) needed, and you still need 55/10 = 5 1/2 275/50 is 5 1/2, not 5/2.

*December 14, 2016*

**algebra**

moving the decimal point 6 places to the right, we get 6.98 * 10^-6

*December 14, 2016*

**Math**

(1+r)^4 = 1.75

*December 14, 2016*

**Math**

How about some parentheses? Just guessing here, I read e^(4x-3) = 2e^(2x) No idea what the final 1 is. Anyway, I'll work this, and then you can fix it if necessary. Taking logs of both sides, we get 4x-3 = ln2 + 2x 2x = 3+ln2 x = (3+ln2)/2 ln(2x+6) - ln(3x-1) = ln(2) (2x+6...

*December 14, 2016*

**Math**

when 1.026^x = 3

*December 14, 2016*

**pre calc**

so, list the values for x calculate and list the values of y. Something hard about that?

*December 14, 2016*

**Math**

A is decreasing when A' < 0 The growth rate G' is maximal when its derivative (G") is zero. Just as G has a max when G' = 0.

*December 14, 2016*

**math**

depends on how many grades you already have. The more low grades you have for the 76% average, the higher grade you will need to raise it to 81%.

*December 14, 2016*

**Business Math**

revenue = price * demand Assuming the usual carelessness with parentheses, r(x) = x*p(x) = x(50/(0.01x^2 + 1)) The maximum revenue is found at x=10. See the graph and other info at http://www.wolframalpha.com/input/?i=x(50%2F(0.01x%5E2+%2B+1))

*December 14, 2016*

**precalculus**

The 2nd difference is not 1 (7-6). The 2nd difference is the sequence of differences of the 1st differences. You have sequence: 7, 6, 7, 10, 15, 22,... 1st diff: -1,1,3,5,7,... 2nd diff: 2,2,2,2,... 2nd ok 3rd. Did you actually try your formula? (Assuming you meant 21.5x) y(1...

*December 14, 2016*

**precalculus**

#1 If you meant Pk=2^(k-1)/k! then Pk+1 = 2^k/(k+1)! #2 If Pk = 7 + 13 + 19 + ...+[6(k - 1)+1] + (6k + 1) Pk+1 = 7+13+...+(6k+1)+(6(k+1)+1) = 7+13+...+(6k+1)+(6k+7) #3 The first step is to show that P(1) is true #4 You assume that 3 + 11 + 19 + 27 + … + (8n - 5) = n(4n - ...

*December 14, 2016*

**MATH FOR LIBERAL ARTS**

well, 1 in = 2.54 cm so just multiply the height (in inches) by 2.54

*December 14, 2016*

**precalculus**

come on -- just plug in k+1 for k: Pk+1 = (2(k+1)-1)/(k+1)! = (2k+1)/(k+1)!

*December 14, 2016*

**precalculus**

the differences are 0,2,4,6,8,... Tn+1 = Tn + 2(n-1) so, Tn = n^2-3n+5

*December 14, 2016*

**precalculus**

I assume you mean n! > 2^n 4! > 2^4 for n>4, n! = 4!*5*6*...*n > 2^4*2*2*2...*2

*December 14, 2016*

**Maths**

The set 1 2 5 7 10 has mean=5 median=5 Now, if you don't want integers, then fudge the values a bit. 1.1 2.1 5 6.9 9.9 The mean is still 5. Since there are an odd number of values, the median must be the center number. If it is 5, then the median is an integer. I see no ...

*December 14, 2016*

**Calc 2 Urgent Surface Area of Revolution Question**

You can do that too.

*December 14, 2016*

**Calc 2 Urgent Surface Area**

Oh yeah. Sorry I did the volume instead. Consider the surface as a pile of circular rings, each with circumference 2?r. So, the surface area is S = ?[0,1] 2?x ds but ds is a small piece of the line, of length ds^2 = dx^2+dy^2 = dx^2 + (4dx)^2 = 5dx^2 S = ?[0,1] 2?x?5 dx = ?5...

*December 14, 2016*

**math**

a fraction of what? a kg? a ton? an ounce?

*December 14, 2016*

**Math**

Is this some kind of truncated triangular pyramid? Your description is a bit vague.

*December 14, 2016*

**precalculus**

same as the others. pick values for ?, figure x and y, then just plot the points! Note that since cos^2?+sin^2?=1, ((x-2)/3)^2 + (y/2)^2 = 1 Looks like an ellipse to me.

*December 14, 2016*