Monday
December 22, 2014

Posts by STEVE


Total # Posts: 27,667

science
the same
November 13, 2014

Math *checking answers*?
Nope - my bad. B,C,D are all the same You want 9.5/3 = x/7 but B,C,D are all 9.5/3 = 7/x
November 13, 2014

Math *checking answers*?
I like C for #2. It's the same as 9.5/3 = x/7
November 13, 2014

calc
I think you want g(x) = 3x√(x+5) on [-5,0] g(-5) = 0 g(0) = 0 So, we want c somewhere in (-5,0) such that f'(c) = 0 f'(x) = 3(3x+10) / 2√(x+5) f' = 0 when 3x+10 = 0 So, c = -10/3 which is in the domain.
November 13, 2014

calc
In that case, g(0) = 0 g(5) = 15√10 Again Rolle's Theorem does not apply. Try again.
November 13, 2014

calc - eh?
g(0) is not defined, since sqrt(-5) is not real. So, g(x) does not satisfy the condition that g(0) = 0 You want to reconsider any part of the question?
November 13, 2014

MATH HELP PLEASE
(13/4)(2x + 3/4) (13/4)(2x) + 13/4 * 3/4 (13/2)x + 39/16
November 13, 2014

Math: Chi Squared
Boy, you don't give much context, do you?
November 13, 2014

Intermediate Algebra
clearly the domain is not (-oo,100) negative percent makes no sense. I'd say the domain is [0,100) C(X) -> oo as x->100, meaning that the harder you try to squeeze out that last bit of pollution, the morse it costs. So, just evaluate C(90). Then double that, since we...
November 13, 2014

Algebra
-3x^5 + 24x^2 factor out -3x^2 and you have (-3x^2)(x^3) + (-3x^2)(-8) -3x^2 (x^3-8) Now recall the factorization of the difference of two cubes, and you have -3x^2(x-2)(x^2+2x+4)
November 13, 2014

Science
F = ma so, a = F/m the x-component is F cos60° and sine for y
November 13, 2014

Molecular Calculations
convert g of Sn to moles. You will need that many moles of O2. Then find the mass for that many moles of O2.
November 13, 2014

Algebra 2
7x^2 = 21x 7x^2-21x = 0 7x(x-3) = 0 This is why we always set stuff to zero. If the product of factors is zero, one of the factors must be zero. So, we have 7=0: never x=0: x=0 x-3 = 0: x=3 Those are the solutions: x = 0 or 3
November 13, 2014

math
0.8 = 8/9 So, you have 10.1 + 8/90 = 101/10 + 8/90 = 917/90
November 13, 2014

Calculus
yes
November 12, 2014

math
at any depth y, the radius of the surface of the water is y/2. So, v = pi/3 (y/2)^2 y = pi/12 y^3 dv/dt = pi/4 y^2 dy/dt Now plug in your numbers.
November 12, 2014

Calculus - PLEASE HELP!!
Looks good to me
November 12, 2014

math
(6.0-0.3)/4
November 12, 2014

Inverses of functions
f^-1(a-1) = -3 a-1 = f(-3) a-1 = 2 a = 3 Not sure just what you're asking
November 12, 2014

math
b/g = 8/5 b = g+135 now just solve for g
November 12, 2014

Pre-Calculus
Look what happens when x gets huge. The equation is basically 5y^2 = 20x^2 y^2 = 4x^2 so the slopes are 2 and -2
November 12, 2014

Math
x-25.6 = 84.3
November 12, 2014

Math
m-4=11 m+u=53 now just find u
November 12, 2014

Math
(100-50)/(3-1.5)
November 12, 2014

Science
you are correct
November 12, 2014

math
s=m m = 4(s-18) Each had 24
November 12, 2014

Pre-Calc/Trig
range is all positive >2, as well as all negative On the interval (-1,1) the numerator is positive and the denominator is negative.
November 12, 2014

Math HELP!
x-10 = 47 x-25.6 = 84.3
November 12, 2014

Algebra HELP!
If the population is P, then 14/50 * P = 30
November 12, 2014

Math - eh?
eh? try that in English
November 12, 2014

Arithmetic Progression
a + a+d = 4 a+9d = 19 a=1 d=2 So, now add T5 and T6
November 12, 2014

Algebra
the two roots have product c and sum 7 Since the coefficient of x is 1, all the rational roots are integers. (x-1)(x-6) = x^2-7x+6 (x-2)(x-5) = x^2-7x+10 ... I think you can see that there are only a few values for c.
November 12, 2014

Calculus
∫v(v^3+5)^2 dv = ∫v(v^6 + 10v^3 + 25) dv = ∫v^7 + 10v^4 + 25v Now just integrate each term.
November 12, 2014

caculus
f"(x) = -4sin(2x) f'(x) = 2cos(2x) + c1 f(x) = sin(2x) + c1*x + c2 Now plug in the initial conditions to find c1 and c2
November 12, 2014

calculus
a(t) = 36t+10 v(t) = 18t^2+10t+c v(0)=9, so c=9 and v(t) = 18t^2+10t+9 s(t) = 6t^3+5t^2+9t+c s(0) = 16, so c=16 and s(t) = 6t^3+5t^2+9t+16 So, find s(11)
November 12, 2014

Calculus
Try this site: http://mathworld.wolfram.com/RiemannSum.html
November 12, 2014

alg 2
think back to algebra I. The QF is x = [-b +/- sqrt(b^2-4a)]/2a So, just plug in your number. The first is x = [-4 +/- sqrt(16-4(1)(-2)]/2 = [-4 +/- sqrt(16+8)]/2 = -4 +/- sqrt(24)]/2 = -2 +/- sqrt(6) Do the same with the others. First step is to get everything on the left ...
November 12, 2014

Algebra 2 HELP plz
t=2 is the correct time. So, plug in t=2 for your formula for h to get the max height. to see when it hits the ground, just set h=0: -16t^2+64t+80 = 0 -16(t+1)(t-5) = 0 so, h=0 at t=5
November 12, 2014

Pre-Calc/Trig...
2(x+5)/(x-3)
November 12, 2014

College Algebra
This is just a parabola, with its vertex at h = -b/2a, or in this case h = 3.817/0.14
November 12, 2014

Math
w(3w-5) = 12 ...
November 12, 2014

College Algebra
y = a(x+2)(x-8) The vertex is midway between the roots, at x=3, so y(3) = 5 a(5)(-5) = 5 a = -1/5 y = -1/5 (x+2)(x-8) See http://www.wolframalpha.com/input/?i=-1%2F5+%28x%2B2%29%28x-8%29
November 12, 2014

College Algebra
usually college algebra students haven't learned about derivatives. However, s(t) is just a parabola, with its vertex at t = 112/32 so, plug that into s(t) to find the max height Note that you got your derivative wrong, anyway.
November 12, 2014

algebra
if x at 2%, then the rest (10000-x) at 5%. So, 10000-x = 3x so solve for x, and the interest earned is .02x + .10(3x) = ?
November 12, 2014

algebra
y = ab^x a*b^2 = 3 a*b^9 = 33 a = 3/b^2, so a*b^9 = 3/b^2 * b^9 = 3b^7 = 33 b = 11^(1/7) a = 3/11^(2/7) y = 3/11^(2/7) * 11^(x/7) = 3*11^((x-2)/7) y(15) = 3*11^(13/7) = k
November 12, 2014

math olympiad
there are many such rectangles. 1 x √88 2 x √85 ... √44 x √45
November 12, 2014

intermediate algebra
the line through (2,3) and (2,0) is x = 2 That is a vertical line. So, the perpendicular line through (2,3) is y = 3
November 12, 2014

Maths
h/10 = 1.8/1.2
November 12, 2014

St Ans School
75-x = x-45 ...
November 12, 2014

Math
How about writing that as 3x - 8y - 4 = 0
November 12, 2014

Math Help
ln√x-8=5 ln√x=13 √x = e^13 x = e^26 log2x+log2(x+2)=log2(x+6) log2(x(x+2)) = log2(x+6) x(x+2) = x+6 x^2+2x = x+6 x^2+x-6 = 0 (x-2)(x+3) = 0 x = 2 or -3 But, log2(x) is not defined for x <= 0, so x=2 is the only solution check: log2(2)+log2(2+2) = log2(2+6...
November 12, 2014

Math
if course not "all reals" plug in just some value and see whether the equation balances. In particular, try x=0: log(4) =?= log(2) I don't think so. What you need to realize is that if 2^x = 2^y or log2(x) = log2(y) or 2x = 2y or 2+x = 2+y or in general, for any ...
November 12, 2014

Maths
1.3/1.8 = h/(7+1.8)
November 12, 2014

Math
you want e^.12x = 3
November 12, 2014

maths
a:b = 3:5 = 12:20 b:c = 4:7 = 20:35 a:b:c = 12:20:35
November 12, 2014

math algebra
Hard to tell, but it appears that you have (x-3)/4 - (y-2)/5 = -1/4 (4-x)/3 + (3-y)/2 = -13/20 which is the same as 5x - 4y = 2 20x + 30y = 209 20x-16y = 8 20x+30y = 209 46y = 201 so, x = 448/115 y = 201/46 Hmmm. Maybe you had x - 3/4 - y - 2/5 = -1/4 4 - x/3 + 3 - y/2 = -13/...
November 12, 2014

Pre-Calculus
recall that cos 2x = cos^2 x - sin^2 x
November 12, 2014

Pre-Calculus
7/12 = 1/3 + 1/4 now review your addition formula for tan(x+y)
November 12, 2014

Pre-Calculus
recall that cos(x-y) = cosxcosy+sinxsiny hence the name cosine -- sine of complementary angle
November 12, 2014

maths
we need (1+x)(0.9) = 1.08 x = 0.20 = 20% check: on $1.00 cost, mark up to $1.20 discount = $0.12, so the final price is $1.08, or 8% profit
November 12, 2014

Pre-Calculus
cos(cos^2+sin^2) don't forget your Algebra I now that you're taking trig!
November 12, 2014

Math
surely the explanation in your text will be more thorough than any offered here. Also, google is your friend...
November 12, 2014

Geometry
s = rθ, so θ = s/r
November 11, 2014

math
12 and 15
November 11, 2014

math
yes, you did
November 11, 2014

Calculus
just use the power rule: d/dx(x^n) = n x^(n-1) so, f'(x) = 3x^2 + 5/x^2
November 11, 2014

Geometry
No, it's November 11. I think you need to provide a little more context. p -> q where p=It's snowing today and q=It is December
November 11, 2014

math
Assuming that's $2.90 each, then 2*2.9 = 5.80 So, now, which has cost more for two packs of batteries?
November 11, 2014

calculus related rates
PV = k V dP/dt + P dV/dt = 0 dP/dt = -(P/V) dV/dt Now just plug in your numbers. By the way, this is true only if the temperature remains constant. More generally, PV = kT
November 11, 2014

calculus inverted cone
when the contents have depth y, the radius of the surface of the liquid is y/2 So, v = pi/3 r^2 y = pi/3 (y/2)^2 y = pi/12 y^3 dv/dt = pi/4 r^2 dy/dt Now just plug in your numbers.
November 11, 2014

Math
e+s = 80 e-17 = 2(2/3 s) Now just solve for e and s, and then get e-s.
November 11, 2014

Math
looks ok. But that depends on what x represents...
November 11, 2014

Math
9^2+35
November 11, 2014

Math
5 * 50/(5+8+7) = 12.5 m
November 11, 2014

College Algebra
there are lots of good graphing sites. Try here: http://www.wolframalpha.com/input/?i=plot+y%3D1%2F2x-3 The two equations describe the same line.
November 11, 2014

Advanced Algebra
3x=4(4-2x)=11 I suspect a typo
November 11, 2014

Pre-Calc/Trig
extrema where 12x^2 - 24x = 0 12x(x-2) = 0 Now apply the 2nd derivative test, and what you know about the general shape of cubics.
November 11, 2014

math
I suspect that V = XYZ So, just multiply the three values
November 11, 2014

Calculus
Go to http://www.wolframalpha.com/input/?i=8ln%28sec%28x%29%29+ and scroll down a bit.
November 11, 2014

Derivatives
Hmmm. You have y = uv, so y' = u'v+uv' = 3x^2(5x-1)^4 + x^3 * 4(5x-1)^3(5) = x^2(5x-1)^3 (3(5x-1) + 20x) = x^2(35x-3)(5x-1)^3
November 11, 2014

Geometry
if the circle has diameter d, then the square has sides equal to the diameter. area = d^2
November 11, 2014

Pre-Calc/Trig
x^5 is positive for x>0 and negative for x<0. So, the graph curves down on the left, and up on the right. All you really need to look at is the highest power of x, which dominates everything for large values of x.
November 11, 2014

math - oops
Oops. That is Nx - My I'll let you make the change and redo the arithmetic.
November 11, 2014

math
Green's Theorem says that ∮CMdx+Ndy = ∫∫RMx+Ny dx dy Nx = 8xy My = 2xy So, we end up with ∫[0,2]∫[x,2x] 10xy dy dx = ∫[0,2] 5xy^2 [x,2x] dx = ∫[0,2] 5x(4x^2-x^2) dx = ∫[0,2] 15x^3 dx = 5x^4 [0,2] = 80
November 11, 2014

algebra 2
Just as with normal fractions, you need to find a common denominator. For example, with 2/3 + 3/5, the commond denominator is (3)(5) Here, you will have a common denominator of (x+y)(x-y) So, you will wind up with (x-y)(x-y)/(x+y)(x-y) + (x+y)(x+y)/(x-y)(x+y) = [(x-y)^2 + (x+y...
November 11, 2014

math
telepathy
November 11, 2014

Algebra please help answer ASAP
(A) 5km/.5hr = 10.0 km/hr (B) 20km/.8hr = 25.0 km/hr (C) 10.0+25.0 = 35.0 km
November 11, 2014

Algebra please help answer thx
1/4 of the guitarists play jazz, so 3/4 play classical. So, 3/4 * 5/8 * 64 = 30
November 11, 2014

math
you are correct, because 6 and23 have no common factors
November 11, 2014

math
every 12 minutes both change at the same time.
November 11, 2014

Math
every 35 days the schedules coincide
November 11, 2014

Precalc/Trig
The first 4 are all ok cot is negative in QII and QIV, and you are right about π±θ. But, that θ is the reference angle, which is always in QI. θ = arccot(5), not -5.
November 11, 2014

Math
(-x+4)log11 = (3x-2)log5 -log11 x + 4log11 = 3log5 x - 2log5 -(log11+3log5)x = -(2log5 + 4log11) x = (2log5+4log11)/(log11+3log5) and, of course, you could go on and say x = log(5^2*11^4)/log(11*5^3) = log366025/log1375 or even log1375366025
November 11, 2014

Grammar
more in keeping with the original might be: The medication had a noticeable positive effect on the patient.
November 11, 2014

physics
Snell's Law says that sinθ/sin30° = 1/1.33
November 11, 2014

math
3 whites out of 10 total balls makes P(white) = 3/10
November 10, 2014

Calculus
Not sure why there are two = signs. Also, Phi is usually an angle, unless it is the golden ratio. I've never seen either one raised to such a power. Where did you get the "equation"?
November 10, 2014

algebra
both domain and range are (-∞,+∞) the domain for all polynomials is the same.
November 10, 2014

Calculus
so, why toss in the product rule as well? :-)
November 10, 2014

calc/trig
to find θ, note that tanθ = 84/130
November 10, 2014

Pages: <<Prev | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | Next>>

Search
Members