Wednesday
September 28, 2016

Posts by STEVE

Total # Posts: 44,202

Math
no idea. what are you doing?
September 28, 2016

Auburn Hugh School
remember the 5-12-13 right triangle. Of course, there are many other non-integer solutions.
September 28, 2016

math!! @bob
a^2=b^2+c^2-2bc*cosA and we don't know A yet
September 28, 2016

math!!
sinB = 1/√10 b/sinB = c/sinC, so √3/(1/√10) = √10/sinC sinC = 1/√3 A = 180 - (B+C) sinA = (180 - (B+C)) = sin(B+C) = sinBcosC+cosBsinC = (1/√10)(√2/√3)+(3/√10)(1/√3) = (2+3√2)/(2√15) Now get a/sinA = b/...
September 28, 2016

Algebra
me, too
September 28, 2016

Math
(8-2)(4+6) = 60
September 28, 2016

pre-calculus
tan = sin/cos = 1/2
September 28, 2016

pre-calculus
sin(-x) = -sin(x)
September 28, 2016

Pre-Calculus
same bogus question. csc(theta) cannot be less than 1.
September 28, 2016

geometry
yes. As you could have verified by plugging in 2 to your function.
September 28, 2016

Math
(20)((-2 + 2) * 2^2 +6) = 120 what do you get for the other one?
September 28, 2016

Math
(3*5)+4-(14/2)=12
September 28, 2016

Trig
θ is in QIV, so x>0 and y<0 cosθ = x/r = 8/17 so, x = 8 y = -15 r = 17 Now recall the other trig functions: sinθ = y/r tanθ = y/x
September 28, 2016

Algebra
sure: y = -2x+3
September 28, 2016

math
substitute 7 for y division property (divide by 8)
September 28, 2016

Math (calculus 3) - correction
correct. good catch
September 28, 2016

Math (calculus 3)
recall that the height y = 1 + 40*sin(pi/6) t - 8t^2 (a) solve for t when y=1 (b) as with all parabolas, the vertex is at t = -b/2a
September 28, 2016

Math
This is called the power set.Any set of n elements has 2^n subsets. Just sum all the powers of 2 from 0 to n-1
September 28, 2016

math plzz help
330/(50+60)
September 28, 2016

computer science
Sorry about the formatting. I meant to say `Twas brillig, and the slithy toves Did gyre and gimble in the wabe: All mimsy were the borogoves, And the mome raths outgrabe. "Beware the Jabberwock, my son! The jaws that bite, the claws that catch! Beware the Jubjub bird, and...
September 28, 2016

computer science
`Twas brillig, and the slithy toves Did gyre and gimble in the wabe: All mimsy were the borogoves, And the mome raths outgrabe. "Beware the Jabberwock, my son! The jaws that bite, the claws that catch! Beware the Jubjub bird, and shun The frumious Bandersnatch!" He ...
September 28, 2016

Geometry
m<3 means the measure of angle 3 But, since we have no diagram, there's no way to tell anything about <1
September 28, 2016

Calculus
y = 4x + [5/sin x] = 4x + 5cscx y' = 4 - 5 cscx cotx y" = 5/2 csc^3(x) (cos(2x)+3) cos(2x)+3 is always positive. on (0,π) csc^3 > 0, so, y is concave up. similarly, y is concave down on (-π,0)
September 28, 2016

physics
since F = GMm/r^2 replacing r by 2r means the F is divided by 2^2
September 28, 2016

science
since g is inversely proportional to r^2, multiplying r by 2 means dividing g by 2^2
September 28, 2016

math
not sure what the special characters are. Copy/paste from word processor documents often mangle the fonts in a browser.
September 28, 2016

Parabola
2x^2-3x+4y+5=0 2x^2-3x+5 = -4y x^2 - 3/2 x + 5/2 = -2y x^2 - 3/2 x + (3/4)^2 = -2y + (3/4)^2 - 5/2 (x - 3/4)^2 = -2y - 31/16 (x - 3/4)^2 = -2(y + 31/32) So, the vertex is at (3/4, -31/32) You know that for the parabola x^2 = 4py here, 4p = -2, so p = -1/2 the focus is at a ...
September 28, 2016

math
the exterior angles of a decagon are all 360/10 = 36° So, 3x+6 = 36 x = 10 For the interior angles (each 144°), 3x+6 = 144 x = 46
September 28, 2016

maths need help
you will not solve this algebraically. Use a numeric approximation or read it from a graph, such as http://www.wolframalpha.com/input/?i=150sinx%3Dx%2B69.98
September 28, 2016

algebra 1, solving polynomials
there are no zeros. All you have is 8*12
September 28, 2016

algebra
1st step: multiply both sides by 17
September 28, 2016

Urgent Math
discs of thickness dx: v = ∫[0,1] πr^2 dx where r=y = 1-x^2 v = ∫[0,1] π(1-x^2)^2 dx shells of thickness dy: v = ∫[0,1] 2πrh dy where r=y and h=x=√(1-y) ∫[0,1] 2πy√(1-y) dy To integrate, use u^2 = 1-y dy = -2u du
September 28, 2016

calculus help me
y = cot(x+y) y' = -csc^2(x+y) (1+y') y' = -csc^2(x+y) - csc^2(x+y) y' y' (1+csc^2(x+y)) = -csc^2(x+y) y' = -csc^2(x+y)/(1+csc^2(x+y)) But, csc^2 = 1+cot^2, so y' = -(1+y^2)/(1+1+y^2) = -(1+y^2)/(2+y^2) or, you can say 1/y = tan(x+y) arctan(1/y) = x+...
September 28, 2016

algebra
good answer, but it does not address the question.
September 28, 2016

math
since distance = speed * time, 90(t-1) = 80(t+1)
September 28, 2016

Maths
sin^-1 (4x^4+x^2) = 1/6 pi 4x^4+x^2 = sin(pi/6) = 1/2 8x^4+2x^2-1 = 0 x^2 = [-2±√(4+32)]/16 = [-2±6]/16 = -1/2 or 1/4 x^2 = -1/2 x = ±i/√2 x^2 = 1/4 means x = ±1/2
September 28, 2016

science
F=ma, so 5 = 18M = 24m M = 5/18 kg m = 5/24 kg For both masses, 5 = (5/18 + 5/24)a a = 72/7 m/s^2
September 28, 2016

Aptitude
how many times around does each hand go? Each time around has circumference 2πr for the hand's radius.
September 28, 2016

math trig
see related questions below. Just use your numbers to follow the logic.
September 28, 2016

Maths
in English you don't lend from. You either borrow from or lend to fix that and all the other typos and try again.
September 28, 2016

Calculus
#1 You know that as x->0 sinx/x -> 1 tanx/x -> 1 You have θ/tan7θ = (1/7) (7θ/tan7θ) -> (1/7)(1) = 1/7 As the graph will show http://www.wolframalpha.com/input/?i=plot+y%3Dx%2F(tan7x),+-0.3+%3C%3D+x+%3C%3D+0.3 #2 some parentheses would help f(x...
September 28, 2016

Math
at r%, 8000(r/100) = 12000((r-1)/100) - 200
September 28, 2016

Math
8000(r/100) = 12000((r-1)/100) - 200
September 28, 2016

Math
A plug in t=0 B as with any parabola, the vertex is at t = -b/2a C see B D plug in t=2
September 28, 2016

Math
(a) and (b) look ok distance = speed * time, so since the time is the same (3.5 hrs), just add up all the speeds and multiply by 210 minutes: 210(8/80 + 6/42 + 15/75) = 93 miles
September 27, 2016

calc
#1: h(x) = k cos x 0 ≤ x ≤ 3π #2: h(x)= 10 − x 3π < x #2: limit as x->3π = 10-3π #1: h(3π) = k cos3π = -k So, you need -k = 10-3π k = 3π-10 #1: h(x) = (3π-10)cosx
September 27, 2016

math
what are path numbers?
September 27, 2016

math
slope: (-4-5)/(-2-1) = -9/-3 = 3 Now, using the point-slope form, y-5 = 3(x-1) at x=0, y=2 2*3+2 = 8 2(3+2) = 10 You took twice the sum of the slope and the intercept, but that was not the question.
September 27, 2016

Calculus
who needs a limit? f = x + 4/x f' = 1 - 4/x^2 So, f'(4) = 1 - 4/16 = 3/4 The tangent line at (4,5) is thus y-5 = 3/4 (x-4) using the limit f(4+h)-f(4) = (4+h)+4/(4+h) - (4 + 4/4) = ((4+h)^2+4)/(4+h) - 5 = ((4+h)^2+4-5(4+h))/(4+h) = (h^2+3h)/(4+h) = h(h+3)/(h+4) Now ...
September 27, 2016

algebra
well, it traveled 90 miles in 1 1/2 hours. So, it is still 1 1/2 hours away at 2:15
September 27, 2016

mathematics
see related questions below
September 27, 2016

Math
87 - 6 - x >= 32 81 - x >= 32 49 >= x so, at most $49 for shirts.
September 27, 2016

math
Plot the points. It will be clear that the line contains (0,-50). Or, now that you know the slope, use the point-slope form of the line with any of the points. How about (5,80) y-80 = 26(x-5) Now plug in x=0 and you will get y = -50.
September 27, 2016

math
no idea what you did wrong, since you didn't bother to show your work.
September 27, 2016

math
first, check to be sure there is a constant slope: (80+310)/(5+10) = 26 (262-80)/(12-5) = 26 (444-262)/(19-12) = 26 So, the slope is 26 For the y-intercept, since x=0 is 1/3 of the way from 5 to -10, the y-intercept is 1/3 of the way from 80 to -310: -50 26 + -50 = -24 Just to...
September 27, 2016

Algebra
you cannot tell by looking at that table?? Really??? Look again.
September 27, 2016

Math
Let the amounts of notes be u,v,w,x respectively. Now just start writing down the facts: 100u+50v+20w+10x = 14400 x = 3w w = 5v v = 5u Now just solve for u. Or, consider if there is a single $100 note. That means there are 5 $50's, 25 $20's, 75 $10's 100+5*50+25*20...
September 27, 2016

Science
work is in Joules, J J = F*d = ma*d= kg-m^s/2 * m = kg-m/s Note I have used kg instead of grams, since MKS uses m,kg,s CGS uses cm,g,s You can use g,m,s if you want, but then the work will not be measured in Joules or ergs.
September 27, 2016

Math
3m wide, but how long? Anyway, if it is x meters long, then you need 3x - (3-2w)(x-2w) = 3x/2 because the area of the whole thing minus the area inside the pathway is the area of the pathway. So, plug in your length for x, and then solve for w.
September 27, 2016

Math
the width+length must be 12. So, start listing pairs of integers which add to 12: 1,11 2,10 ... 6,6
September 27, 2016

Math
twenty tens means a 2 in the hundreds place now work from that, one item at a time.
September 27, 2016

math
26 = 5+(3^2-6)*7 play around with the others a while. There aren't that many places to put the parens.
September 27, 2016

Algebra
see http://www.jiskha.com/display.cgi?id=1474984965
September 27, 2016

math
the length + width must be 12, so the following dimensions will work: 1x11 2x10 ... 6x6
September 27, 2016

Algebra
correct But note that x is a variable name × is the multiplication symbol
September 27, 2016

Maths grade 8
If there are n sides, then each exterior angle is 360/n degrees. each interior angle is thus 180 - 360/n = 180(n-2)/n degrees.
September 27, 2016

de~movire
note that x^4-x^3+x^2-x+1 = (x^5+1)/(x+1) see what you can do with that...
September 27, 2016

math
since distance = speed * time, 3x = 2.5(x+2)
September 27, 2016

stationary point
You need both partials to be zero. That is, #1: 3y^3 + 2xy = 0 #2: 3(3x+1)y^2 + x^2 = 0 From #1, we get x = -3y^2/2 Plug that into #2 and you get y^2 = 4/15 So, z has stationary points at (-2/5, ±2/√15)
September 27, 2016

Math
2x^2 - 128 = 0 x^2 = 64 x = ±√64 = ±8
September 27, 2016

Math
56/(77-56)
September 27, 2016

mathematics need help
There are lots of proofs of the chain rule on line. You can find one here, if you scroll down some http://tutorial.math.lamar.edu/Classes/CalcI/DerivativeProofs.aspx So, now you know that if y = f(g) and g is a function of x, then dy/dx = df/dg * dg/dx You can see that treated...
September 27, 2016

mathematics need help
this is just the chain rule. I assume you have seen the proof of that. That said, just substitute x for f(x).
September 27, 2016

Physics .. hard problem
oops. After falling for 5.88 seconds, the student is caught, then 3.81 seconds later they land gently on the ground.
September 27, 2016

Physics .. hard problem
At time t=x, the Rocketeer catches up with the student. At that point (the Rocketeer having arrived with some unknown velocity v), their height and speed are student: 427 - 4.9x^2 9.8x Rocketeer: 427 - v(x-5) - 4.9(x-5)^2 v + 9.8(x-5) So, we match their heights and we get 427...
September 27, 2016

Math
v^2 = 2as 35^2 = 2a*18 a = 34 m/s^2 You have no idea how long it took to accelerate. The units in your calculation are all jumbled up.
September 27, 2016

math
8/x + 3/4 < 2 8/x < 5/4 now you can easily find x.
September 27, 2016

math
set x=0: 0 + 4y = 15
September 27, 2016

Math
first, find the common denominator for each problem. Then you can work with the fractions more easily.
September 27, 2016

Engineering Math
well, apparently P(a-bP) = bP(300 − P) aP - bP^2 = 300bP - bP^2 so, a = 300b dP/dt = P(300b-bP) = bP(300-P) Try plugging that in. You already know what the logistic growth function looks like, so that should guide your efforts some.
September 27, 2016

maths need help
If there are n terms, we have a + ar = x ar^(n-2) + ar^(n-1) = y a(1+r) = x ar^(n-2)(1+r) = y now divide r^(n-2) = y/x r = (y/x)^(n-2)
September 27, 2016

maths trig need help
clearly not true at x = pi/4. The LS is undefined while the RS = √2.
September 27, 2016

math
3x - 1(19-x) >= 32
September 27, 2016

physics
h = (v sinθ)^2 / 2g
September 27, 2016

Algebra
there are lots of linear regression calculators online, such as http://ncalculators.com/statistics/linear-regression-calculator.htm
September 27, 2016

further maths
you can start by dividing by 5 everywhere 5x-30x+25=0
September 27, 2016

Math
7^{-10}
September 27, 2016

physics
°C = 5/9 (°F-32) now just plug in F=1800
September 27, 2016

physics
no "fever" 37°C = 98.6°F
September 27, 2016

maths
if the last digit is 4, then there are 6! ways If the last digit is 2 or 8, then there are only 6!/2! ways because of the duplicate 4s. So, there are only 2*6! total ways
September 27, 2016

Urgent Math
First, do a long division x^3/(x^2+1) = x - x/(x^2+1) for the 2nd term, let u=x^2+1
September 27, 2016

Math
either 2x+50 = 180 or 2*50+x = 180
September 27, 2016

Math
Let u=18x-x^2-77 log_3(u) exists if u>0 log_5(log_3)u)) exists if log_3(u)>0, or u > 1 log_4(log_5(log_3(u))) exists if log_5(log_3(u)) > 0, or log_3(u) > 1, or u > 3 So, we need 18x-x^2-77 > 3 18x-x^2-80 > 0 (10-x)(x-8) > 0 8 < x < 10
September 27, 2016

math
After 20 min. there will be 2^20 bacteria
September 27, 2016

Further mathematics
Draw a triangle with adj. side L hypotenuse 1 opp. side: √(1-L^2) Now you can just read off the other trig functions and use them in your expression.
September 27, 2016

Math
yes
September 27, 2016

pre-calculus
I'm sure if you review the properties of ellipses you can come up with the values given at http://www.wolframalpha.com/input/?i=ellipse+(x%2B3)%5E2%2F24+%2B+(y-5)%5E2%2F49%3D1
September 27, 2016

math
uh, 5% more, right?
September 27, 2016

college trip
a) 2 rev/hr = 4π rad/hr b) 4π*125 ft/hr now make that into mi/hr
September 26, 2016

Math
I get 2+(2+1) + 3+(3+1) add each number to "itself plus one"
September 26, 2016

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