Saturday
July 30, 2016

Posts by Steve

Total # Posts: 42,180

math
huh?
May 9, 2016

Trigonometry
the height in feet can be found using h/5280 = tan6°
May 8, 2016

Geometry
V = 18*w*12 where the width is w.
May 8, 2016

math: pre-calculus
by definition, e^(ln x) = x ln(e^x) = x ln and e^ are inverse functions, just like x^2 and √x Assuming no typos, I see ln(e^3y)+ln(ey)-ln(e^4) = ln(e^3y * ey / e^4) = ln(y^2) = 2ln(y)
May 8, 2016

math: pre-calculus
you want p = a e^(kt) clearly p(0) = 53 p = 53 e^(kt) p(3) = 90, so 53 e^(3k) = 90 e^(3k) = 90/53 3k = ln(90/53) k = ln(90/53)/3 = 0.1765 so, we have p(t) = 53 e^(.1765t) Now you try the others, lest you be accused of homework dumping...
May 8, 2016

geometry (please help)
The area of the triangular base is (1/2)(9)(10) = 45 There are two of those, for a total of 90 There are three rectangular faces of area 9*10+9*9+9*13.5, for a total of 292.5 Total area is thus 90+292.5 = 382.5 in^2
May 8, 2016

math: pre-calculus
note that this is just log(x) shifted left 3 and down 8. So, now you can relate its properties to those of h(x)
May 8, 2016

math
just plug in the data and solve for w. Then you can get the length. w(3w-2) = 65 Of course, it also helps to know that 5*13 = 65 ... just sayin'
May 8, 2016

algerbra
since distance/speed = time, (1600/400) + (1600/320) = ?
May 8, 2016

Math Algebra
since distance/speed = time, 200/(x+3) = 200/(x-3) - 1
May 8, 2016

math
290-50 = 240 240/60 = 4 so, in 4 more hours
May 8, 2016

Calculus
V(0) = 500,000 V(5) = 405,000 (V(5)-V(0))/(5-0) = -19,000 ft^3/min
May 8, 2016

math , steve or damon pls
right on both of them.
May 8, 2016

math
pi, not pie! 2pi(r^2+rh) = 2pi(25+75) = 200pi Now just multiply that are by the cost, which is .0450/cm^2
May 8, 2016

calculus
let u = 2x you know lim sin(u)/u, right?
May 8, 2016

damonnnn math help
since multiplication is commutative, 6t^3 * 6t^3 = 6*6 * t^3*t^3 = 36t^6 t^3*t^3 = t*t*t * t*t*t = t^6, not t^9 add exponents when multiplying powers
May 8, 2016

Geometric series
a = -1 r = 3 Sn = (-1)(3^n-1)/(3-1) = (1-3^n)/2 = -3280 1-3^n = -6560 3^n = 6561 n = 8
May 8, 2016

calculus
what, you forgot your Algebra I? (x+1/x)^2 = x^2 + 2 + 1/x^2 Surely you can handle each of those terms...
May 8, 2016

math
figure the volume in ft^3, then multiply by how many gal/ft^3. That will give you how many gallons will fit. I have no idea how many gallons are actually in the tank...
May 8, 2016

calculas
let the distance from 3rd base be x. Then the distance z from home is z^2 = 90^2 + x^2 so, to find dz/dt, 2z dz/dt = 2x dx/dt So, find z when x=20, then plug in dx/dt and x.
May 8, 2016

Maths - eh?
If B is a point, how can a line be perpendicular to it?
May 8, 2016

mathematics-permutation and combination
The two boys are separated by 10 others on each side, right? Now you can easily figure the solution.
May 8, 2016

math
Just draw a diagram. All those right angles help a lot. XZ/2800 = tan(90-63)° 2800/XP = cos(90-25)°
May 8, 2016

math
x/180 = cot 27°
May 8, 2016

Trigonometry and Right Triangles!
the sides are in the ratio 1:√3:2 so if the hypotenuse is 16, then the sides are 8,8√3,16 and the perimeter is 24+8√3
May 8, 2016

Math
2x+5x = 4.27 x = .61 So, they have 1.22 and 3.05 lbs. Now you can decide how much has to be given so they have the same amount.
May 8, 2016

math
180/x = tan 27°
May 8, 2016

math
with A at (0,0) we just add the x- and y-displacements to get the final location: <4,0>+<0,-3>+<-3.06,-2.57> = <0.94,-5.57> Now you can find the distance and bearing.
May 8, 2016

Maths
x+y=120 0.9x + 1.2y = 120 80+40 = 120 72+48 = 120
May 8, 2016

Math
If the diamond is just a rotated square, then its diagonal is 3, so its area is 9/2. So, the rectangle has width 3 and area 27, so its height is 9.
May 8, 2016

math
Draw a diagram. It will be clear that using the law of cosines, the distance d is found using d^2 = 300^2 + 200^2 - 2*300*200 cos33°
May 7, 2016

MATH
1/14 (196x+17-10)= (14/20)(20x+12x) has no solution since (14/20)(20x+12x) = 14x + 42/5 and 1/14 (196x+17-10) = 14x + 1/2 and there is no value of x such that 14x+42/5 = 14x + 1/2
May 7, 2016

MATH
The equation 1/14 (196x+17-10)=______ (20x+12x) has no solution. The equation (4x+24/122)=_____ (x+16/122)
May 7, 2016

MATH!
not sure what question is answered by the 4, but you are correct in assuming that the equation is an identity.
May 7, 2016

MATH!
The equation 1/14 (196x+17-10)=______ (20x+12x) has no solution. The equation (4x+24/122)=_____ (x+16/122) Im sure the answer for the second one is 4, (4x+24/122) = 4 (x+6/122)
May 7, 2016

math
The answer is as follows: 9-3÷1/3+1 9-3*3/1+1 9-9+1 0+1 Answer = 1
May 7, 2016

math
other interpretations of 9 minus 3 divided by 1/3 plus 1 are (9-3)/(1/3) + 1 = 6*3+1 = 19 (9-3)/(1/3 + 1) = 6/(4/3) = 9/2 9 - 3/(1/3) + 1 = 9-9+1 = 1 9 - 3/(1/3 + 1) = 9 - 9/4 = 27/4 As you can see, using math symbols is a lot less ambiguous than just words, and grouping ...
May 7, 2016

math
you have correctly factored the left side. What has that to do with the right side? Or is that 16/22 a typo?
May 7, 2016

math
The equation 1/14 (196x+17-10)=______ (20x+12x) has no solution. The equation (4x+24/122)=_____ (x+16/122) Im sure the answer for the second one is 4, (4x+24/122) = 4 (x+6/122)
May 7, 2016

math
The equation 1/14 (196x+17-10)=______ (20x+12x) has no solution. The equation (4x+24/122)=_____ (x+16/122) Im sure the answer for the second one is 4, (4x+24/122) = 4 (x+16/122)
May 7, 2016

math
R = R1 + R2 = 10 + 15 = 25Ω
May 7, 2016

math
clearly a permutations problem, since the order of award matters. So, there are 50P3 ways to arrange the selections.
May 7, 2016

math
the desired point will be the center of the circle passing through the three points. So, if that is (h,k), we have (x-1)^2 + (y-1)^2 = r^2 (x-7)^2 + (y-1)^2 = r^2 (x-1)^2 + (y-9)^2 = r^2 Now, you can solve those to find (h,k) and r, or you can note that the three points form a...
May 7, 2016

calculas 1
f(0) = 0 f(9) = 9^9 (wow!) (f(9)-f(0))/9 = 9^8 f'(x) = 9x^8 so, you want c such that f'(c) = 9^8 9c^8 = 9^8 c^8 = 9^7 c = 9^(7/8) ≈ 6.84 ∊ [0,9]
May 7, 2016

math
The equation 1/14 (196x+17-10)=______ (20x+12x) has no solution. The equation (4x+24/122)=_____ (x+16/122) Im sure the answer for the second one is 4, (4x+24/122) = 4 (x+16/122)
May 7, 2016

math
if f(x) = x^2+bx+c, we have (x^2+bx+c) + (x^2-bx+c) = 2x^2 2x^2+c = 2x^2 so, c=0 and f(x) = x^2+bx f(2016) = 0, so 2016^2 + 2016b = 0 b = -2016 f(x) = x^2 - 2016x = x(2016-x) f(10) = 10(2016-10) = 10(2006) = 20060
May 7, 2016

trig
not quite sure what "double angle of tan" means, but if you want tan(u) where u is in QI and sec(u) = 7/2, then draw the triangle. clearly tan(u) = √45/2 = 3√5/2. So, tan(2u) = 2tan(u)/(1-tan^2(u)) = 2(3√5/2)/(1-45/4) = -12√5/41
May 7, 2016

maths-factor
1/(x-3) < -1 what do you mean factors? You want a solution set If x-3 > 0, then 1 < 3-x x < 2 Not possible if x>3 If x-3 < 0 or x < 3, then 1 > 3-x x > 2 So, the only solutions are 2<x<3 verify here: http://www.wolframalpha.com/input/?i=1%2F%...
May 7, 2016

geometry
the distance from (-6,-8) to (0,0) is 10. So, (x+6)^2 + (y+8)^2 = 10^2
May 7, 2016

geometry
Write the standard equation for the circle center (-6,-8), that passes through (0,0). I know that the formula would leave the 1qstr part as (x+6)+(y+8) I'm not sure about the radius when it goes through (0,0)
May 7, 2016

integral calculus
no idea what box you're talking about. Probably an integral sign which does not render in your font. Judging from the answer produced by wolframalpha.com http://www.wolframalpha.com/input/?i=integral+dx%2F%283x^3-5%29^3 you have some major tricks to use.
May 7, 2016

algebra
the max height is where t = -b/2a = 3 h(3) = 256 ft h=0 when t=7
May 7, 2016

calculas 1
You give no limits on the area.
May 7, 2016

calculas
clearly the rectangles are bounded at x = 0, π/6, π/3, π/2, 2π/3, 5π/6, π So, evaluate g(x) at the boundaries and add up the areas. What do you get? There are plenty of online calculators for this to check your work.
May 7, 2016

calculas 1
Have you tried laying out a few rows? I'm sure you will see a pattern. You will be adding up sequences of even or odd numbers...
May 7, 2016

Geometry
Since s=rθ, the circumference of the base of the cone is 15 * 4π/3 = 20π So, the radius of the base of the cone is 10. Now you can find the height of the cone, and thus the volume.
May 7, 2016

math
recall that x = vcosθ t y = vsinθ t - g/2 t^2 dy/dx = dy/dt / dx/dt = (vcosθ - gt)/(-vsinθ) -cotθ + g/(vsinθ) t we want dy/dx = tan(θ/2) = (1-cosθ)/sinθ = 1 - cotθ -cotθ + g/(vsinθ) t = 1 - cotθ t = vsinθ/g
May 7, 2016

math
just use your equation of motion, and find when its slope (derivative) is tan(alpha/2).
May 7, 2016

Trig
If we call the lengths OA and OB x and y, then we have, using the law of cosines, x^2+y^2-√3 xy = 1 That is just an ellipse with its extreme values at x=2 or y=2. So, the maximum value of OB is 2.
May 7, 2016

Calculus
well, the two curves intersect at (±√(10/3),40/3), so the area is 2*integral[0,√(10/3)] (x^2+10)-(4x^2) dx = (40/3)√(10/3)
May 6, 2016

Calculus
work = force * distance, so ∫[0,25] 30-.1x dx
May 6, 2016

Math
Come on, man. The area is just a 6x4 rectangle. Rotating it around the y-axis jives you a cylinder with r=6 and h=4, so its volume is 144π Or, if you must use calculus, v = ∫[0,6] 2πx*4 dx = 144π Or, using the Theorem of Pappus, it is the area of the ...
May 6, 2016

math
yes it is
May 6, 2016

Math Help Please
anything that ends in .9... is an integer. So, 0.999999... = 1 1.999999... = 2 4.999999... = 5 and so on
May 6, 2016

Programming
Oops. I dislayed the total, not the average. Change that to avg /= n Display "The average score for Student #",s," is ",avg
May 6, 2016

Programming
how about something like this: minSubjects = 8 maxSubjects = 12 Display "Enter the number of students: " enter students for s = 1 to students   Display "Enter the scores for student #",s   enter scores   n = length(scores) &...
May 6, 2016

MATH Please Help Please
f(n) is a sequence of integers, and the domain is all integers. f(x) is a function whose domain is all real numbers, not just integers.
May 6, 2016

Pre-Cal (Trig) Help?
try arccos(.957269)
May 6, 2016

Pre-Cal (Trig) Help?
all you need is the sum formula for cosines. in other words, cos(A+B) = .957269 A+B = 16.81°
May 6, 2016

maths-word problem help
A&B together can do 1/12 + 1/18 = 5/36 of the job in a day So, it will take them 36/5 * 2 = 72/5 days. or 14 2/5 days After 14 days, they have each worked 7 days, so 7 * 5/36 = 35/36 of the job is done. On the 15th day A works 1/3 of a day to finish up the last 1/36 of the task.
May 6, 2016

Math (Ms. Sue)
why all the duplications? I only see H1 H2 H3 H4 TT TH Those are the only outcomes if only two events are to be considered.
May 6, 2016

math
In better notation, M(x) = 50 * 2^x change the 50 to 450
May 6, 2016

math
x((1+r)^2-1) = 440 x((1+r)^3-1) = 728 ((1+r)^3-1)/((1+r)^2-1) = 728/440 r = 1/5 = 0.2 = 20%
May 6, 2016

calculus
x^3 = at^2 3x^2 x' = 2at x' = 2at/3x^2 x" = (2a)(3x^2) - (2at)(6xx') -------------------------------         9x^4 2ax - 4at(2at/3x^2) -----------------------------      3x^3 (6ax^3 - 8a^2t^2)/(9x...
May 6, 2016

college algebra
ln(310*3x) ln(930x) ... Hmmm I suspect you mean log base 3 instead of ln. ln is the natural log, using base e=2.71828... So, since all your logs are base 3, let's just write log, since there is no confusion. log(10)+log(x) = log(10x) log(10-x) cannot be simplified log(10/x...
May 6, 2016

college algebra
Since it starts in 2000, and 2001 is the next year, I'd pick 2,419,774 Not sure how the 5 values represent a population over 8 years.
May 6, 2016

Math
r = 95 b = 5g r+g = b-189 95+g = 5g-189 4g = 284 g = 71 so, b = 355 95+71+355 = 521
May 6, 2016

math
xy=42 x+y=3 There are no real solutions to this. However, if we suppose there is a typo, note that 6*7 = 42 6+7 = 13
May 6, 2016

Geometry
π/3 * 2^2 * 4 + 2π/3 * 2^3 = 32/3 π
May 6, 2016

math
3/10 * 2/9
May 6, 2016

5th grade math
y < 2x y < 2*15 y < 30
May 5, 2016

math
(6.4+12.3)/2 h = 37.4 9.35h = 37.4 h = 4
May 5, 2016

math
better use Heron's formula, if all you have is the sides.
May 5, 2016

Pre calculus
sinθ = √((1-cos2θ)/2) = √(1/8) since 2θ is in QIV, θ is in QII
May 5, 2016

Algebra
both ok
May 5, 2016

mason
There are 7C2 = 21 ways to pick the 1st two horses, leaving 5 to arrange in the other places. So, there are 21 * 5! ways to finish the race.
May 5, 2016

Math
oops - 3/10 of 2/3 = 2/10 = 1/5 1/3 + 1/5 = 8/15 so, 7/15 x = 35 x = 75 check: on Monday read 1/3, or 25 pages, leaving 50 unread On Tuesday read 3/10 of 50 = 15 pages, leaving 35 unread
May 5, 2016

calculus help me plz
dx/((x-1)sqrt(x^2-2)) OK. First step is a trig substitution. x = √2 sec(u) x^2-2 = 2tan^2(u) dx = √2 sec(u) tan(u) du now the integral is sec(u)/(√2 sec(u)-1) du see what you can do with that.
May 5, 2016

alebra
both look good.
May 5, 2016

trigonometry
review your basic trig functions. You will see that the height is 38tan67°30' + 38tan18°20'
May 5, 2016

math
If the amount poured is x gallons, then (35-x)/(4.5+x) = 7/2 find x, and the rest is easy.
May 5, 2016

math. compounding interest
3500 * .075/2
May 5, 2016

math
use your distance formula: √(5^2+8^2)
May 5, 2016

math
clearly, since the box has length 8, the paper must be longer.
May 5, 2016

Trigonomentry
Draw a diagram. If we label the triangle ABC, with sides a,b,c then the law of sines tells us sinC/10.2 = sin117.5°/35 Now you have angles B and C, so you know A=180-(B+C) a/sinA = sin117.5°/35 or a^2 = 35^2+10.2^2 - 2*35*10.2 cosA
May 5, 2016

help maths partail sum
∑ 1/(6k-2) This is just a modified harmonic series, so it diverges. That is, you know that ∑ 1/k diverges. So, this does as well. Don't know a formula for the nth partial sum.
May 5, 2016

Math
just plug in your calculator. What do you get?
May 5, 2016

calculus plz help me
dx/((x-1)sqrt(x^2-2)) OK. First step is a trig substitution. x = √2 sec(u) x^2-2 = 2tan^2(u) dx = √2 sec(u) tan(u) du now the integral is sec(u)/(√2 sec(u)-1) du see what you can do with that.
May 5, 2016

calculus plz help me
see the steps here. http://www.integral-calculator.com/ Interestingly, wolframalpha.com simplifies it a lot.
May 5, 2016

Math
Review your basic trig functions. The height is 1.15 + 95.5tan31.5°
May 5, 2016

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