Thursday
August 25, 2016

Posts by STEVE

Total # Posts: 42,762

physics
First, check that it hasn't yet hit the ground. Finding it has not, then get the resultant of the horizontal and vertical velocities √(10^2 + (9.8*3)^2) at an angle of 71° below the horizontal
July 25, 2016

business math
1200(1+.086*6) + 500(1+.086*3) or 1200(1+.086*3) + 1700(1+.086*3) = 2900(1+.086*3)
July 25, 2016

Mathematics @Tris
Interesting answer. How did you arrive there?
July 25, 2016

Mathematics
√(61^2 + 28^2) = ...
July 25, 2016

Mathematics
40/(3+5) = 40/8 = ...
July 25, 2016

math
6*8^2 = 6*64 = ...
July 24, 2016

math
A(4) = 80/3 = 26.6666 A(4.01) = 26.6999 slope ≈ .0333/.01 = 3.33 As always, the slope is the rate of change. In this case, how fast the drug is being absorbed 4 <time units> after ingestion.
July 24, 2016

geometrey
pretty sure it's area.
July 24, 2016

Java
still Math
July 24, 2016

math
a graphical or numerical method would do the trick, if you don't have calculus to help.
July 24, 2016

math
(a) revenue-cost = profit y = p(-(p+5)(p-17)) - (75+12(-(p+5)(p-17))) = -(p^3-24p^2+59p+1095) (b) R>C means P>0 The roots are at -5.2, 13.1, 16.1 From what you know about the shape of cubics, P>0 in the interval (13.1,16.1) (c) y' = -(3p^2-48p+59) y' = 0 at p=...
July 24, 2016

MATH
check your previous post before reposting the same question: http://www.jiskha.com/display.cgi?id=1469374770
July 24, 2016

Java
Math class
July 24, 2016

Math
let u = 9^x then, 9^(2x) = (9^x)^2 = u^2 Thus all you have is u^2+4u = 21 u^2+4u-21 = 0 (u+7)(u-3) = 0 so, u = -7 or u=3 But, u = 9^x ...
July 24, 2016

Math
this is just a quadratic in 9^x. So, it factors out as 9^(2x) + 4(9^x) - 21 = 0 (9^x + 7)(9^x - 3) = 0 9^x cannot be -7, so you are left with 9^x = 3 x = 1/2
July 24, 2016

Maths
do a synthetic division on each polynomial using x-p. If p is a common root, then both remainders will be zero. Eliminate p and you will wind up with a polynomial in a,b,c. Solve for b.
July 24, 2016

Some Please Help me - PreCalc
All you need to do is show that x^2+y^2=1. Don't forget your Algebra I now that you're in pre-cal! (√31/7)^2 = 31/49 (-3√2/7)^2 = 18/49 Looks like they add up to 1, so the point is on the unit circle.
July 24, 2016

Maths
google is your friend. I found http://math.stackexchange.com/questions/1629163/how-to-find-derivative-of-sin-sqrtx-using-difference-quotient
July 24, 2016

Calculus
when x=3, y=4 2x dx/dt + 2y dy/dt = 0 or, losing the factor of 2, x dx/dt + y dy/dt = 0 Now just plug in your numbers.
July 24, 2016

Algebra
well, did you actually try it? 7/6 < 5 check 5 < 1/(1/6) = 6 check So, yes, that works.
July 24, 2016

Algebra
x + 1.28x = 3420
July 24, 2016

mathematics
42
July 24, 2016

Math
49 and 0
July 24, 2016

Math
x(12-x)
July 24, 2016

MATHEMATICS
4 years ago, the average age was 22. So, now it is 26. After the adoption, since the average age now is 24, The new kid is x years old, where 26*4+x = 24*5 x = 16 So, he was 14 when adopted 2 years ago.
July 24, 2016

Physics
angular velocity: 2π/40 = π/20 rad/s speed: 40πm/40s = π m/s velocity: -80m/40s = -2 m/s in the direction from start to finish.
July 24, 2016

physics
p = mv now just plug in your numbers
July 24, 2016

Math
Assuming the usual sloppiness with parentheses, I parse you equation as (x-1)/(x^2-9) + 1/(x-3) = 2/(x+3) using a common denominator of (x+3)(x-3), we have (x-1) + 1(x+3) - 2(x-3) -------------------------- = 0       (x-3)(x+3) assuming x is not 3...
July 24, 2016

math
I cannot parse un first second through which height it will move ??
July 24, 2016

maths
6x + 4y*-3x + 5x - 2x*3y do * first, so 6x - 12xy + 5x - 6xy Now add like terms: 11x - 18xy
July 24, 2016

Math
distance = speed * time, so if the van's speed is v, then v-28 = 2/3 v
July 24, 2016

Math
Suppose n groups of beads were used for the necklace. Then 3n yellow beads and 2n blue beads were used. So, counting just the blue beads, 35 + 2n = 4*3n This is not possible if only whole groups of 2 blue and 3 yellow beads were used.
July 24, 2016

Maths & numeracy
compare $6.48/250g = $.0259/g vs $10.65/375g = $0284/g
July 24, 2016

Maths
1/x = logn(a) 1/y = logn(c) (x-y)/(x+y) = (1/y - 1/x)/(1/y + 1/x) = logn(c/a)/logn(c*a) logb(c)-logb(a) = logb(c/a) logb(c)+logb(a) = logb(c*a) The two ratios are equal.
July 23, 2016

math
LCM(6,10) = 30
July 23, 2016

math
120% = 6/5 y + 6/5 y = 550
July 23, 2016

math
a 25% increase is a factor of 5/4 So, you need 4/5 of the width for the area to stay the same (5/4 l)(4/5 w) = lw So, what % decrease is 4/5?
July 23, 2016

Math
see related questions below. Just solve 7.8+3.5sin[pi/6(t-3)] = 10.29
July 23, 2016

Math
(9^x)^2 + 4(9^x) - 21 = 0 (9^x + 7)(9^x - 3) = 0 ...
July 23, 2016

Math
300*1.055^n = 3000
July 23, 2016

math
5/8 - 1/4 = 3/8 So, 3/8 x = 15
July 23, 2016

math
so what's the trouble? They gave you the equation y = R(p)-C(p) = N(p)*p - C(p) = -p(p+5)(p-17) - (75+12(-(p+5)(p-17))) = (12-p)(p+5)(p-17) - 75 You can expand that if you want. What does it mean? Revenue-Cost = Profit.
July 23, 2016

math
Fix the typo. And do you mean 6/(2x-y) ?
July 23, 2016

Algebra
since the area scales by the square of the linear factor, the sides are in the ratio √(32/63) = √(16*2 / 9*7) = 4/3 √(2/7) I'll let you take it from there.
July 23, 2016

physics
get out your graph paper and plot the motion. Clearly the distance walked is 10+5 = 15 Now, where did he end up? How far is that from where he started?
July 23, 2016

mathematics
a+9d = 40 + a+4d a+14d = 127 solve for a and d, then find S30 = 30/2 (2a+29d)
July 23, 2016

Math
x(x+2) = 195 find x, and then x+2 p = 2(x + x+2)
July 23, 2016

Physics
time to accelerate 10m/s / 4m/s^2 = 2.5s deceleration takes twice as long, since the rate is half as great. Now figure the distance using the good old formula s = vot + 1/2 at^2 for each part of the trip.
July 23, 2016

Math
good work, but if you are going to include the units in your expressions, it is important to be careful with them: 48hours x 5seconds=240 hour-seconds what you need to do is make sure that the units cancel properly. 48hr x 5s/hr = 240s
July 23, 2016

Linear equations in 1 variable
Add up their value: 5x + 2(3x) = 77 Now find x and thus 3x.
July 23, 2016

Maths
2(x+y) = 62 xy = 198 x+y=31 y = 31-x x(31-x) = 198 x^2-31x+198 = 0 (x-9)(x-22) = 0 ...
July 22, 2016

math
a(bx-c) = d-(x+e) abx-ac=d-x-e (ab+1)x = ac+d-e x = (ac+d-e)/(ab+1)
July 22, 2016

Math
Hmmm. 7.8sin (pi/6(t-3)) = 10.29 sin (pi/6(t-3)) = 1.319 <--- ?? I suspect that you have left out a term in the definition of h(t). Fix it and then proceed with the solution.
July 22, 2016

Math
2 trenches = 3*5 = 15 man-hr 7 trenches = 7/2 * 15 = 105/2 man-hr (105/2 man-hr) / (5 man) = 21/2 hr or, 10 hr 30 min
July 22, 2016

RE
The only thing you have to remember is that since the two sides of an equation are equal (hence the name), if you do the same thing to both sides, they remain equal. Your goal is to isolate the variable on one side, so the other side is just its value. Now, when you say you ...
July 22, 2016

math
well, you know that the equation for a parabola with vertex at (0,0) directrix y = -p is x^2 = 4py Your parabola has been shifted so the vertex is at (-2,4), so you want (x+2)^2 = 4p(y-4) Your directrix is at y = 1, which is 3 units below the vertex, so p=3 (x+2)^2 = 12(y-4) ...
July 22, 2016

math
log1/2(x-1)+log1/2(x+1)-log1/√2(7-x)=1 You seriously need to learn how to use parentheses. Also, the final result will depend on the base of the logarithms. I shall assume base 10. Assuming you meant log(1/(2(x-1)))+log(1/(2(x+1)))-log(1/(√2(7-x)))=1 log (1/(2(x-1...
July 22, 2016

Maths
the height on the nth bounce is 100*0.8^n So, the geometric sequence for the bounces is a = 100 r = 0.8 Each bounce is a round trip, except for the 0th trip, so the distance traveled is 2*100/0.2 - 100 = 900 ft The real-world distance of course will be slightly less than that.
July 22, 2016

math
the number who passed either or both is 30+20-8 = 42 so, ...
July 22, 2016

math
or, since 15 = 3*5, multiply by 5/5 and you have 3/7 = 15/x 15/35 = 15/x x = 35
July 22, 2016

Calculus
well, x is cut off both sides, and x is the box's height, so v(x) = (18-2x)(12-2x)(x)
July 22, 2016

math
Divide the $420 into 10 parts of $42 each. A gets 3 parts, or $126 B gets 7 parts, or $294 In order for A to get 180, either B gets 420 or a gets 3/7 of the total, not 3/7 of B's share.
July 22, 2016

Futher maths
I'll just use x, for ease of typing tanx + 2secx = 2cotx + 3cscx A strange mixture of functions, so I'll just use sine and cos: sinx/cosx + 2/cosx = 2cosx/sinx + 3/sinx (sinx+2)/cosx = (2cosx+3)/sinx So, assuming that cosx and sinx are nonzero, sinx(sinx+2)-cosx(2cosx+...
July 22, 2016

Math
what's the problem? Just calculate the distance and time as needed, and the average speed is distance/time. For (a), A-B is 25km A-C is 10km So, B-C is 15km C-A takes 1.5 hr B-A takes 3.5 hr stop at C takes 0.5 hr So, the B-C leg takes 1.5 hr 15km/1.5hr = 10km/hr The rest ...
July 22, 2016

English
zombie apocalypse runaway vehicle fire army ants avalanche chainsaw maniac
July 22, 2016

Math
if you review the definition of the cotangent function, then you can see that with a height of h, h cot19° - h cot37° = 60
July 21, 2016

Physics
each bulb is a separate branch of the circuit, and so has the same voltage drop. Since they have the same resistance, each bulb gets a current of 1.5V/6.3Ω = 0.238A Note that 1/Rt = 0.317, so Rt = 3.15 = 6.3/2 Ω
July 21, 2016

math
one measurement is worth a thousand expert opinions. Buy some chips, fill the jar. Empty them out, count them. In the interest of accuracy, it will be best to eat the chips and repeat with a new batch. Maybe several times!
July 21, 2016

Civics.
I agree with D, but I'd hardly consider Brazil a smaller country. Its area is bigger than the continental USA, and it has vast natural resources. Granted, a lot of them are in the jungle, and that makes them harder to extract.
July 21, 2016

Msth
actually, keeping track of the units, 1,130mi / 25mi/gal = _______ gallons Multiply the gallons by $2.60/gal to get the dollars
July 21, 2016

Physics
G(M)(2M)/(3x)^2 = KGM^2/x^2 2GM^2/9x^2 = KGM^2/x^2 2/9 = K
July 21, 2016

statistic
Consult your Z table to see how many std away leaves 4.5% Multiply that by 0.36 and add it to the mean. Play around with Z table stuff at http://davidmlane.com/hyperstat/z_table.html
July 21, 2016

math
pair them up in this way: -35,35 -34,34 ... The sum of all those pairs is zero. So, which numbers are left over? Add them up.
July 21, 2016

math
after a 30% markup the price is cost * 1.30 After a 15% discount, the price is cost * 1.30 * 0.85 = cost * 1.105 That price is $99, so 1.105 * cost = 99 cost = 99/1.105 = 89.59
July 21, 2016

math
cost * 1.30 * (1-0.15) = 99 cost = 99/1.105 = 89.59
July 21, 2016

Math CSET
There is no easy way. The actual math formula is simple, but hard to do by hand. I suggest that you just have to know the values for 1,2,3 std from the mean. Just as it is best if you just know the trig values for common angles.
July 21, 2016

Algebra
Assuming "a rate at x rate per min" means "a rate of x ft per min", then 4000 - xy
July 21, 2016

PHYSICS
will squash you like a bug.
July 21, 2016

algebra - incomplete
sorry - you need another equation.
July 21, 2016

Electric Circuits
I = E/R Now just plug in your numbers.
July 21, 2016

general math
K(x) = 15.00x for x <= 50 12.50x for 50 < x <= 75 Apparently you had some choices, but they're not here. I got my answer by reading the text provided. How else?
July 21, 2016

math
LCM(25,30) = 150 minutes 11:00 + 2:30 = 13:30, or 1:30 pm
July 21, 2016

math
Reiny did this one already. See the related questions below.
July 21, 2016

Physics or Math
The Toyota goes 350km in 5 hours. The Kia has gone the same distance in 7 hours. So, the Kia's speed must be 50 km/hr
July 21, 2016

math
for the triangle, 6*5 = 1/2 * 12 * h Now, knowing h, the side length s can be found using s^2 = 6^2 + h^2 For the towers, the distance z is z^2 = 16^2 + (40-10)^2
July 21, 2016

Physics
distance = time * speed. So, 5*70 = (5+2)*x
July 21, 2016

Calc
we want to maximize xyz subject to the constraint that 5xy+3(xy+2xz+2yz) = 1000 Using Lagrange multipliers, we find that x=y, and λ=2.1516 and z=4λ That means a local max occurs at (6.455,6.455,8.607) A nice article on Lagrange multipliers, with an example similar to...
July 20, 2016

Geometry
see earlier post better yet, graph the two functions and see the shifts
July 20, 2016

Geometry
I think she meant y=(x−5)^2+5 → y=(x−0)^2+0 shift left 5 and down 5
July 20, 2016

Chemistry
DrBob222 did it last night. See the related questions below.
July 20, 2016

maths - sloppy
The rectangle is x meters what? wide? long? do you mean x m^2, the area?
July 20, 2016

Math
There are 4 cubes per foot, so in terms of cubes, the prism is 8/14 x 4 x 5 Since you want whole cubes you are out of luck, since 2/14 < 1/4, the size of a cube. I suspect a typo. Fix it and then apply the logic.
July 20, 2016

Math
draw your triangle. secθ = r/x and x<0, so θ is in QII or QIII x = -3 r = √20 y = ±√11 Now just recall that tanθ = y/x, so it will be ±√11/3, depending on the quadrant.
July 20, 2016

Physics
I'm sure you have seen examples of this simple circuit. (a) R = 2+3 (b) 1/R = 1/2 + 1/3 I = E/R in each case.
July 20, 2016

physics
2r/πr = 2/π π/2 is the ratio between its distance traveled (πr) and its displacement (2r).
July 20, 2016

math
right you are. Should be "greatest." If I had to choose (and I don't) I'd assume sloppiness and pick 11.
July 20, 2016

mathematics
I'd say zero, since today is Wednesday!
July 20, 2016

math
a = b*l = b * b^2 = b^3 da/dt = 3b^2 db/dt 40 = 3*64 db/dt db/dt = 5/24 l = b^2 dl/dt = 2b db/dt = 2*8 * 5/24 = 10/3
July 20, 2016

math
hmmm. where is D? If your inequalities hold, then clearly CD < AC < AD
July 20, 2016

math
draw a diagram. Review your basic trig functions. Now it is clear that if the height is h ft, h cot 78°15' + h cot 59°47' = 500
July 20, 2016

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