Sunday
February 19, 2017

Posts by STEVE

Total # Posts: 48,629

Calculus
x&sup0;¹²³-5
January 4, 2017

Calculus
x&sup5;-5
January 4, 2017

Calculus
x^²-5
January 4, 2017

Calculus - incomplete
Fill in the missing text that did not get pasted
January 4, 2017

Math
well, sums are not directly related products and quotients, so I think more information is needed. I will note, however, that a product is just a short way to write a sum. 4*3 = 4+4+4 or 3+3+3+3
January 4, 2017

Math
Note that the two points lie on the same horizontal line: y = -6 Graph that line segment, and it will be clear where the other two points lie, since width+height=13
January 4, 2017

pre Calc
come on. A vertical line has the same x-coordinate everywhere. Look at the point it passes through. Vertical lines are of the form x=h Horizontal lines are y=k
January 4, 2017

pre calc
Looks like you need to review your Algebra I... 8x ? 3y + 6 = 0 3y = 8x+6 y = 8/3 x + 2
January 4, 2017

pre Calc
clearly the slope is -3.5 Now think f=mt+b
January 4, 2017

Number Theory
4x+7 = 2(mod 15) 4x = -5(mod 15) 4x = 10(mod 15) so, what can x be so that 4x = 5k+10 for some k?
January 4, 2017

precalc
you know that cos(u) might either decrease or increase, depending on u. surely t/52 increases when t does. !!
January 4, 2017

Math
x = -2 is a vertical line. So, what is the horizontal line through the point? x = -5 is parallel to x = -2, not perpendicular.
January 4, 2017

Math
F = ma just add up the vectors, after dividing by the mass.
January 4, 2017

Math
surely you can graph the lines y = 2/3 x y = -2 y = -3x+1 then just take the pieces you need.
January 4, 2017

Pre Calc
the slopes must be the same, so (8-1)/(2-a) = (1-6)/(a+2-12) a = 30
January 4, 2017

profit&loss mathematics
come on. B paid 20% of A's cost: 1.20A C paid what A did: B/1.20 = 08.3333B So, B lost 16.666 % maybe my math looks as funny to you as your texting does to me...
January 4, 2017

profit&loss mathematics
B = 1.20A C = A = B/1.20 = (5/6)B so, that is ...
January 4, 2017

Maths
?x^2 h = 800 h = 800/(?x^2) The area is two circles plus a curved cylinder, so a = 2?x^2 + 2?xh the result follows, so just find x such that da/dx = 0
January 4, 2017

mathematics
sorry - a=20 ! :-(
January 4, 2017

mathematics
you must be studying geometric sequences, so just note that this is the sum of the sequence with a = 12 r = 3/5 Now just use your formula for the infinite sum: s = a/(1-r)
January 4, 2017

am I right ? or no?
you are correct that b^x is growth if b>1 and decay if b<1
January 4, 2017

Maths
convert the area to m^2 area = length*width, so divide by the width to get the length
January 4, 2017

Maths
0.5ha * (10000m^2/ha) / 12.5m = 400m
January 4, 2017

algebra - duh @Reiny
It usually helps to read the problem carefully. Nice work, Reiny
January 4, 2017

algebra
x+y <= 9x-5y 6y <= 8x 3y <= 4x You might also want to consider x+y <= |9x-5y|
January 4, 2017

Maths
n = d-7 (n+2)/(d+9) = n/d (d-7+2)/(d+9) = (d-7)/d d(d-5) = (d-7)(d+9) d^2-5d = d^2+2d-63 7d = 63 d=9 check: original fraction: 2/9 modified fraction: 4/18 = 2/9
January 4, 2017

Maths
if you have a unix system, you can use the bc calculator for arbitrary precision, as well.
January 4, 2017

Math
1/4 of 2 cups is ??
January 4, 2017

math
((3200/1.60)/4)^2 * 1.20/100 = 3000
January 4, 2017

Math
there are 4 choices for each digit, so 4^4 total ways. 3/4 of them start with a number less than 7, right?
January 4, 2017

Math;);)
the two points lie on the unit circle, clearly 54-19 degrees apart. The angle is 35°. or, use the distance formula to find the vector u-v. Then use the law of cosines to find the included angle.
January 4, 2017

math
Just plug in n=5: a5 = 6*5-4 = ?
January 3, 2017

Math
well, the equations is (x-(2-3i))(x-(2+3i)) = 0 ((x-2)+3i)((x-2)-3i) = 0 (x-2)^2 + 3^2 = 0 x^2-4x+4 + 9 = 0 x^2-4x+13 = 0 a+b = -4+13 = 9
January 3, 2017

Math
try using letters like a,b,c instead of the special characters that are getting mangled.
January 3, 2017

maths
if x<0>=0 then 4/(x<0>)^2 is undefined. I'll assume that x<n+1> = 4/(x<n>^2+5) If so, then x<0> = 0 x<1> = 4/(0^2+5) = 4/5 = 0.8 x<2> = 4/(0.8^2+5) = 4/5.64 = 0.7092 ... The actual root ? 0.72408 If I got the formula wrong, then ...
January 3, 2017

maths
areas grow as the square of the linear factor. So the areas are A:B = (8:10)^2 = 64/100 = 16/25 A/160 = 16/25 A = 16*160/25 = 102.4 cm^2
January 3, 2017

math
tan(x) = h/d = 4d/d = 4 x = arctan(4) = 76° for part b, h decreases, because x decreases.
January 3, 2017

math
3^-n = 0.2 3^n = 1/0.2 = 5 (3^4)^n = (3^n)^4 = 5^4 = 625
January 3, 2017

Maths
V = 4/3 ? r^3 A = 4? r^2 = 3V/r = ?(36?V^2) Now just plug in your numbers.
January 3, 2017

Algerbra
He will need (253.5/6)^(3/2) * 2 = 549.25 kg of clay So, he will need 55 10kg bags
January 3, 2017

Surfaces of cones
?r?(r^2+h^2) = 2160? (12x)?(144x^2+256x^2) = 2160 (12x)(20x) = 2160 x^2 = 9 x = 3 so, the volume is ?/3 r^2h = (?/3) (24*3)^2 (16*3) = 82944? V = 82944 cm^3
January 3, 2017

Maths
just expand the left side. It will be the same as the right side. One way to start would be (3x-1)(x+5)(4x-3) = 3x(x+5)(4x-3)-(x+5)(4x-3) Now, (x+5)(4x-3)=4x^2+17x-15 so you can proceed with = 3x(4x^2+17x-15)-(4x^2+17x-15) = ...
January 3, 2017

Math
sorry - only one equation.
January 3, 2017

Math
useless problem. 6 apples - 2 oranges =
January 3, 2017

Math
Q = 10-P so, P^2-Q^2 = 40 P^2-(10-P)^2 = 40 20P-100 = 40 20P = 140 P = 7 So, Q = 3 check: 7^2-3^2 = 49-9 = 40
January 3, 2017

algebra(difference of two squares)
Your answer is clearly incorrect, since you want integers. The problem is that odd numbers differ by 2, so (n+2)^2-n^2 = 336 now it should work better.
January 3, 2017

math
5i
January 3, 2017

Math
T = k?L using L'=1.4L instead, we have T' =k?L' = k?(1.4L) = k?L ?1.4 = T?1.4
January 3, 2017

trigonomentry hope steve or damon reiny can help
Lat's just use u and v for ease of typing x = cosu + i sinu y = cosv + i sinv (x-y)/(x+y) = (cosu-cosv) + (sinu-sinv)i ------------------------------- (cosu+cosy) + (sinu+siny)i Now multiply top&bottom by the conjugate of the denominator, collect terms, and recall that tan...
January 3, 2017

Maths
AB = 2x = 1.7 CD = 3x = 2.55 BD/CD = tan52° BD = 2.55 tan52° = 3.264
January 3, 2017

math
1800/1350 * 3
January 3, 2017

MATH
3:9
January 3, 2017

Math
If n were nabbed, then letting j = the jaywalkers, we have n/4 = j Now go on to the next sentence...
January 3, 2017

Math
well, check the differences: 1-1=0 4-3=1 9-7=2 16-13=3 25-21=4 So, how does that relate to n?
January 3, 2017

Mathmatics
If the two numbers are n and n+1, then we have (n+1)^2 - n^2 = n^2+2n+1-n^2 = 2n+1 = n + n+1
January 3, 2017

Math (please check my answer!!)
correct
January 3, 2017

math
looks good to me. S=131 L=452 = 2*131+190 = 131+321
January 3, 2017

Math
I suspect it was 30 by 20 to start with.
January 3, 2017

Maths
but yes, you are in fact correct.
January 3, 2017

Maths
huh? a,b,c are the coefficients in the equation, as usual!
January 3, 2017

Math
Reiny's answer is correct, according to (1 + x/(1-x) / (1 - x/(1-x) ) The domain is all reals except x = 1/2 or 1 Even though the domain of 1/(1-2x) only excludes x = 1/2, we also need to exclude x=1 since f(1) and g(1) are undefined, so f(g(1)) cannot be defined either.
January 3, 2017

math coordinate geometry
fix what's missing and maybe we'll give it a shot.
January 3, 2017

maths
tanx+tan2x+?3tanx tan2x=?3 tanx+tan2x = ?3 - ?3tanxtan2x tanx+tan2x = ?3(1-tanx tan2x) (tanx+tan2x)/(1 - tanx tan2x) = ?3 tan3x = ?3 ...
January 2, 2017

Math
(x+1)^3 = ?(x^2)
January 2, 2017

math
yes
January 2, 2017

science
Looks more like B and C to me. It takes force to turn the turbines. The weight of the water is force. The height it falls increases the momentum of the water, which is transferred to the turbines. Water which is not flowing (falling) exerts no force to turn the turbines.
January 2, 2017

Math
100000*(56/100)^(t/(2010-1990)) massaged as needed
January 2, 2017

trigonomentry ps
oh, yes. x=3?/2 also works.
January 2, 2017

trigonomentry
you can rewrite it as sinx + cosx + cos^2(2x) = 0 clearly x= 3?/4, ?, 7?/4 are some solutions. To find them all will take some doing. working with our equation, -sinx = cos^2(2x) + cosx square both sides to get sin^2(x) = cos^4(2x) - 2cos^2(2x)cos(x) + cos^2(x) 1-cos^2(x) = (...
January 2, 2017

Algebra
(x+1)^3 = ?(x^2)
January 2, 2017

Math
50+10m
January 2, 2017

algebra
2x-2 < -12 2x < -10 x < -5 2x+3 > 7 2x > 4 x > 2 So, x < -5 or x > 2 Work the other in like wise. Just clear the fractions first to make things easier.
January 2, 2017

integral calculus
see Mycah's post below
January 2, 2017

business maths
a worthy goal, to be sure.
January 2, 2017

SAT MATH
Line m has slope -3/8. So, using the point-slope form, y-(r-2) = -3/8 (x-r) or, 3x+8y = 11r-16 Now solve that along with 8x-3y=n and set the intersection to be (r,r-2). Then solve for r in terms of n.
January 2, 2017

integral calculus
Hmmm. I get x/2 - sin(2x)/4
January 2, 2017

Add math
?((x-4)^2+(y-8)^2) = 2?((x+2)^2+(y-3)^2) square both sides and collect terms. It will be a circle. http://www.wolframalpha.com/input/?i=circle+((x-4)%5E2%2B(y-8)%5E2)+%3D+4((x%2B2)%5E2%2B(y-3)%5E2)
January 2, 2017

Add math
1+y+1+2y+2+13+16 = 6*9 Find y, then get ?^2 as usual.
January 2, 2017

Add math
max area when square. So, 12x = 4-x
January 2, 2017

Add Math(rate of change)
v = ?r^2h dv/dt = 2?rh dr/dt + ?r^2 dh/dt Now just plug in your numbers to get dr/dt Note that since h=2r, dh/dt = 2 dr/dt Or, since h=2r, v = ?r^2h = 2?r^3 dv/dt = 6?r^2 dr/dt
January 2, 2017

Analytic Geometry
the slope is 1. So, the line is y = x+1
January 1, 2017

mathematics
a + a+d = 4 a+9d = 19 a+4d + a+5d = ?
January 1, 2017

calculus-add
see your earlier post for #1 For #2, review your techniques for 1st order linear ODEs, and see whether you can get the solution given here: http://www.wolframalpha.com/input/?i=(x-2)+dy%2Fdx+%3D+1-3y(x-1)%2F(x%2B1) Solve the homogeneous equation using partial fractions, and ...
January 1, 2017

calculus
huh? simple separation of variables. (2y-1) dy = (3x^2+1) dx y^2-y = x^3+x + C Using your point (1,2), find C: 4-2 = 1+1+C C = 0 y^2-y = x^3+x y = (1±?(4x^3+4x+1))/2
January 1, 2017

Analytic Geometry
C is the center, so 4 = (-1+x)/2 6 = (y+8)/2 ...
January 1, 2017

Analytic Geometry
Draw your line segment with the labeled points. It should be clear that LM=10 Now you can plug in the lengths required to evaluate the expression.
January 1, 2017

shaekh
a ba - a bb
December 31, 2016

Algebra
z/z = 1 so, multiply by that.
December 31, 2016

Algebra
the elevation is already given as an integer...
December 31, 2016

Algebra
commutative means they can be written in reverse order. So, ...
December 31, 2016

algerbra
you have the numbers. Just use them.
December 31, 2016

Algebra
we usually think of win as positive lose as negative
December 31, 2016

integral calculus
coth * sinh = cosh so your integral is just 1/cosh^2(2x) dx = sech^2(2x) dx That's just a standard form (almost).
December 31, 2016

Algebra
google is your friend: http://m.nextgurukul.in/nganswers/ask-question/answer/The-ratio-of-the-sum-of-n-terms-of-two-APs-is-7n14n27/Arithmetic-Progressions/21214.htm
December 31, 2016

Surds
?(2+?3) = ?((4+2?3)/2) = ?((1+2?3+3)/2) = ?((1+?3)^2/2) ...
December 31, 2016

Math
using similar triangles, the tree is 24/4 = 6 times as high as Palmer's eye.
December 30, 2016

Math
well, y = 35.00 + 1.50 x, so ...
December 30, 2016

Math
just use the [power rule to find the derivative of each term: d/dx x^n = n*x^(n-1) As for finding the roots, derivatives don't help much with that. But, digging back into your Algebra I skill set, note that f(x) = -x^2(x+1) + 16(x+1) = (16-x^2)(x+1) ...
December 30, 2016

math
Using brute force, since a = (-1+?23 i)/6 27a^4 = (49+11?23 i)/6 and so does 11a+10
December 30, 2016

math
see related questions below
December 30, 2016

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