Sunday

February 26, 2017
Total # Posts: 48,814

**Math**

The same way I already showed you ...

*December 18, 2016*

**Mensuration**

Just subtract the bare floor from the total area: 10*8 - (10-2*2)(8-2*2)

*December 18, 2016*

**Algebra II Honors**

(25+x)(10+x) = 1000 Or, you could just double the dimensions. Then the area grows by a factor of 4, to 1000 ft^2.

*December 18, 2016*

**Math**

sure. at t=0, we are at the maximum value. But sin(0) = 0 and sin(t) is a maximum 1/4 period later. Go to the website and play around with different shift values. If you replace 3 with 0, you will see that the graph starts at y=10, but we want to shift it so that it starts at ...

*December 18, 2016*

**Math**

I suspect they are expecting you to say the cosine model is simpler, since then there is no shift needed: we start at the max or min. Then all you need is y = ±4cos(?/6 x) + 10

*December 18, 2016*

**Math**

high tide = 14m low tide = 6m so, the center line is (14+6)/2 = 10m, and the amplitude is (14-6)/2 = 4m The 1/2 period (max to min) is 6 hours, so the period is 12 hours. SO, we can start with y = 4sin(?/6 x) + 10 However, sin(x)=0 at x=0 (high tide), and we want y to be at ...

*December 18, 2016*

**Math**

next steps: 2x^2+x-21 = 0 (2x+7)(x-3) = 0 x = -7/2 or 3 since real-world figures do not have negative dimensions, the rectangle is thus 3x7. Which you probably already guessed, since the only factors of 21 are 3 and 7!

*December 18, 2016*

**calculus**

it sure is (x-x^3)-(x^2-x) = -x^3-x^2+2x You can't combine x^2 and x^3 to make x^5!! They're added, not multiplied.

*December 17, 2016*

**calculus**

since f > g on (0,1), the area is just ?[0,1] (x-x^3)-(x^2-x) dx = 5/12

*December 17, 2016*

**math**

Since the diameter is symmetric about (0,0), B=(-3,5)

*December 17, 2016*

**math**

note that y grows by 19 when x grows by 1. So, start with y = 19x Now adjust that so it fits the table.

*December 17, 2016*

**Calculus Finals Review sheet!! Explanation needed**

inflection points are where y"=0. That is, where y' has a max or min. [[x-2]]/x -> [[3.5-2]]/3.5 = 1/3.5 upward acceleration is where the velocity is increasing. That is, where the graph is concave up.

*December 17, 2016*

**algebra**

try typing your expressions in at wolframalpha.com

*December 17, 2016*

**algebra**

without the typo, we have (3x-2)(2x-3) = 3x(2x-3) - 2(2x-3) = 6x^2-9x - (4x-6) = 6x^2-9x - 4x+6 <------- = 6x^2-13x+6

*December 17, 2016*

**Dilation**

just multiply all the coordinates by 2.

*December 17, 2016*

**Go with @Joe**

Sorry about my typo. e^.07t is correct

*December 17, 2016*

**Math**

e^(1.07t) = 2

*December 17, 2016*

**precalculus**

the odd powers of (-y)^k have a minus sign.

*December 17, 2016*

**precalculus**

1 1 1 Now form new rows by adding 1 at each end and each element is the sum, of the two above it. google is your friend. It will provide many discussions of this topic.

*December 17, 2016*

**a.p.**

or, we know that Sn = n/2 (2a + (n-1)d) = 3n^2+2n an + n(n-1)/2 d = 3n^2+2n an + d/2 n^2 - d/2 n = 3n^2+2n d/2 n^2 + (a - d/2)n = 3n^2+2n d/2 = 3 so d=6 (a-3)=2 so a=5 Tn = 5 + 6(n-1) = 6n-1

*December 17, 2016*

**algebra**

-3(4y-9)+2(2y+6) = (-3)(4y) + (-3)(-9) + (2)(2t) + (2)(6) = ...

*December 17, 2016*

**Math - Coordinate Geometry**

huh? You can't apply the distance formula? AB = ?((5+2)^2+(4-3)^2) = ?(49+1) = ?50 CD = ?((-3-4)^2+(-4+3)^2) = ?(49+1) = ?50 So, AB=CD Now do the same steps for AD and BC.

*December 17, 2016*

**maths**

the fixed setup cost must be 75-45=30 so, 1000 copies cost 30 + 10*15

*December 17, 2016*

**maths**

100 per 10,000 so, use that to find for another 23,000 people: 675+230=905

*December 17, 2016*

**Math**

path is total area minus the pool: (8+1)(5+1) - 8*5 = ?

*December 17, 2016*

**Math**

the dimensions are 8x and 5x. So, 8x * 5x = 169 40x^2 = 169 x^2 = 169/40 x = 13/?40 Now you can determine 8x and 5x

*December 16, 2016*

**Cardinality of Intersection**

15+60-x = 63

*December 16, 2016*

**math**

This should help out: http://www.jiskha.com/display.cgi?id=1317372273

*December 16, 2016*

**math**

well, 8 = 2^3 a^27 = (a^9)^3 ...

*December 16, 2016*

**precalculus**

#1 ok #2 will be the x^4 term #3 will be the x^10 y^2 term #4 Nope. It is 8C6 (3x)^2 (-2y)^6 = 28*3^2*2^6 x^2y^6 = 16128 x^2y^6

*December 16, 2016*

**precalculus**

correct

*December 16, 2016*

**Algebra**

A+69-13 = 107

*December 16, 2016*

**math**

It is (somewhat) clearly a motion problem. v(t) = t^2-2t+1 s(t) = 1/3 t^3 - t^2 + t + C Now, knowing that v(1) = 4 does not help to find C. Moreover, given the equation, it is clear that v(1)=0, not 4. So, let's assume that s(1) = 4. Then we have 1/3 - 1 + 1 + C = 4 C = 3 ...

*December 16, 2016*

**Algebra**

x^2 + 10x = 18 x^2 + 10x + 25 = 18+25 (x+5)^2 = 43 x+5 = ±?43 x = -5±?43 work the other in like wise.

*December 16, 2016*

**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*