Sunday
February 26, 2017

Posts by Steve

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

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