Tuesday

September 27, 2016
Total # Posts: 44,101

**Physics**

Starting at the top of the ramp, the rider's height is h(t) = 1.60 sin23° t - 4.9t^2 So, find t when h=0 The rider's velocity when he hits the ground is Vx = 1.60 cos23° Vy = 1.60 sin23° - 9.8t So, the speed v at time t is found using v^2 = Vx^2 + Vy^2

*September 24, 2016*

**maths**

google is your friend: (a) https://answers.yahoo.com/question/index?qid=20131112055820AAxrUAf (b),(c) Check out Riccati equations y' = y^2 + q(x)y + p(x)

*September 24, 2016*

**Maths Percentage**

22/24 * 100 = ?

*September 24, 2016*

**Math**

If the length of AB is x, then AP = 2x/5 AQ = 3x/7 PQ = AQ-AP = 3x/7 - 2x/5 = 2 Now just solve for x

*September 24, 2016*

**maths**

infinitely many. Any point on the x-axis will do.

*September 24, 2016*

**math**

geez. How many ways are there to add 18 + 16?

*September 24, 2016*

**Physics**

340m/s * 2s = 680m

*September 24, 2016*

**Math**

48/(5+(11-8)) - 7

*September 24, 2016*

**Maths - Woe Is Me!**

fix the typos And what does p>+-24 mean. I get that +- means ±, but what does p>±24 mean? Also what are you supposed to do with 18x^2+2px+32 ?? factor it? solve for the roots? find p such that it is a perfect square? what, oh, what? Wooooeeee is meeee!!

*September 24, 2016*

**Geometry**

You know that AP+PQ+QB = a Now, AP = 2PQ = 2BQ That means that PQ = QB and that gives us 2PQ + PQ + PQ = a 4PQ = a PQ = a/4 Let M be the midpoint of QB Let N be the midpoint of AP AM = AP+PQ+ QB/2 = a/2 + a/4 + a/8 = 7a/8 NM = AP/2 + PQ + QB/2 = a/4 +a/4 + a/8 = 5a/8 Draw and ...

*September 24, 2016*

**Geometry**

first, recall that supplementary means they add to 180. So, now you know that A) The two angles are x and x-40 x-40 + x = 180 B) The two angles are 5x and 4x. So, 5x+4x = 180 So, just solve for x, and then you can work out the angles.

*September 24, 2016*

**Trigonometry**

see related questions below google can also help out

*September 24, 2016*

**maths~log**

just for ease of readability, let's say u = log5x v = log3y Then we have 2u+3v=8 6u+2v=2 This has the solution u = -5/7 v = 22/7 Unusual for a problem of this kind, but anyway... log5x = -5/7, so x = 5^(-5/7) log3y = 22/7, so y = 3^(22/7)

*September 24, 2016*

**maths**

I think your sum-to-product formulas will make this just drop out easily.

*September 24, 2016*

**Maths**

AB^2 + BC^2 = AC^2 1 + 1 = 2

*September 24, 2016*

**Maths**

assuming this is an isosceles triangle, I'd say they are both (180-65)/2

*September 24, 2016*

**math**

6 1/2 + 7 2/3 = 6 3/6 + 7 4/6 = ...

*September 24, 2016*

**Algebra**

plug in your data at http://www.gregthatcher.com/Mathematics/GaussJordan.aspx for the details, and confirmation of your answer >wink wink<

*September 24, 2016*

**Math**

DNE means Does Not Exist, so (a) is the choice of choice.

*September 23, 2016*

**Physics**

the range R = v^2/g sin2θ Now just plug in your values

*September 23, 2016*

**Chemistry**

25/800 = 1/32 = 1/2^5 so, it will take 5 half-lives

*September 23, 2016*

**Math**

Try plugging in you numbers here and see whether it is the same. The range is R = v^2/g sin2θ

*September 23, 2016*

**Math**

so, what do you get?

*September 23, 2016*

**Math**

√n is defined only for n>=0 So, the domain of √(2x+1) is (2x+1)>=0, or x >= -1/2 similarly for the other. There is always a domain.

*September 23, 2016*

**Math**

so, after t years, it is 41250 * 1.02^t

*September 23, 2016*

**Physics**

F = ma = 0.39 * 930√2

*September 23, 2016*

**Math , trigonometry**

h/20 = tan(47)

*September 23, 2016*

**physics**

F=ma plug in your numbers and evaluate a. Watch the units.

*September 23, 2016*

**Newtons Cooling Method**

-1.002 ≈ 1, so let's use T(t) = -53e^-t + 89.50 = 85.25 53e^-t = 0.25 e^-t = .004717 t = -ln .004717 = 5.3566

*September 23, 2016*

**math**

−2(x+2/3)+1=5 −2(x+2/3) = 4 x + 2/3 = -2 ...

*September 23, 2016*

**ODE Piecewise**

y'-y = 1: y = ce^x - 1 for 0<=x<=1 y'-y = -1: y = ce^x + 1 for x>1 y(0) = 1 means c=2, so y = 2e^x - 1 for 0<=x<=1 If we want y to be continuous, then since y(1) = 2e-1, y = (2 - 2/e)e^x + 1 for x>1 Thus, y(2) = (2 - 2/e)e^2 + 1 = 2e^2-2e+1

*September 23, 2016*

**Engineering Math**

Start with Newton's Law of cooling. Using your numbers, with To the initial temperature, T(t) = 10 + (To-10)e^(-kt) Now you have T(1) = 10 + (To-10)e^-k = 40 T(2) = 10 + (To-10)e^-2k = 25 (To-10)e^-k = 30 (To-10)e^-2k = 15 (To-10)^2 e^-2k = 900 (To-10) e^-2k = 25 Now ...

*September 23, 2016*

**5th grade math**

14+2=6+2x(3+2)

*September 23, 2016*

**Engineering Math, Newtons Cooling Method**

Your DE yields v = c e^(-2t) + 4.9 v(0) = 0 means c = -4.9, so v(t) = 4.9 - 4.9e^(-2t) (a) plug in t=1.5 (b) v(∞) = 4.9

*September 23, 2016*

**Physics**

v = 30*sin30° - 9.8t it reaches max height when v=0.

*September 23, 2016*

**maths**

Man. some messy algebra! Clearly there are horizontal asymptotes at y = ±b and curve passes through (a,0). The shape seems to preclude any simple equation or parametric equations. Maybe more later.

*September 23, 2016*

**Algebra**

Treat it as you always do fractions. Multiply by the denominator to clear the fraction: -54/x = -6 -54 = -6x Now it's a cinch, right? |x| is the "size" of x, regardless of whether it is positive or negative. It is defined as |x| = x if x >= 0 |x| = -x if x <...

*September 23, 2016*

**Algebra**

shift left: x -> x+4 stretch: y -> 3y shift up: y ->y+5 g(x) = 3(x+4)^2+5

*September 23, 2016*

**GEOMETRY**

The change in coordinates from A(-6, -3) to B(3, 1) is (3-(-6),1-(-3)) = (9,4) 1/3 of the difference is thus (3,4/3) (-6,-3) + (3,4/3) = (-3,-5/3) (-3,-5/3) + (3,4/3) = (0,-1/3) (0,-1/3) + (3,4/3) = (3,1) The first two points divide AB into 3 equal parts.

*September 23, 2016*

**science**

adage: opposites attract

*September 23, 2016*

**Math**

well, 5+7 = ?

*September 23, 2016*

**math**

50 <= c <= 150

*September 23, 2016*

**math**

I'll just use x for ease of typing (note the use of parentheses to make things clear!) 1/(1+sinx) + 1/(1-sinx) =((1-sinx)+(1+sinx))/((1+sinx)(1-sinx)) = 2/(1-sin^2(x)) = 2/cos^2(x) = 2sec^2(x) By far the most useful trig identity is sin^2(x) + cos^2(x) = 1 It pops up in ...

*September 23, 2016*

**Math**

well, if they are not equal, one must be less than the other.

*September 23, 2016*

**Calculus**

if you don't know that the slope of the curve is given by the derivative, I suggest more study, or google will provide many discussions. Assuming that you believe that the derivative of a function gives the slope of the curve at any point, then you just have to remember ...

*September 23, 2016*

**Operating System**

once you get past the sloppy English, you might provide a little more information, doncha think?

*September 23, 2016*

**12**

well, the numbers are 2k 2k+2 2k+4 2k+6 multiply them and you have 2^4(k(k+1)(k+2)(k+3)) Now, two of those numbers must be even, so the product is divisible by 2^6 In addition, the product of 3 consecutive numbers is divisible by 6, so 2^7*3 = 384 divides

*September 23, 2016*

**math**

original fraction: (x-3)/x (x-3+4)/(x+4) = 3/4

*September 23, 2016*

**value**

each hour, 1/2 - 1/3 = 1/6 of the tank is filled. That should help some...

*September 23, 2016*

**Maths, science**

maximum volume is achieved when the box is a cube. The area of the box is c^2, so each face has area c^2/6 That means the side has length c/√6. v = (c/√6)^3 = c^3/(6√6) Hmmm. Better double-check my math.

*September 23, 2016*

**Chemistry**

figure the moles each mole fills 22.4L at stp

*September 23, 2016*

**dosage calculations**

looks ok to me

*September 23, 2016*

**Calculus**

f'(a) = R means f(a) = Ra + C But, if f is odd, C=0 So, f(-a) = -f(a) = -Ra

*September 23, 2016*

**Algebra**

reflected: y = |-x| stretched: y = 1.5|-x| shifted: y = 1.5|-x| - 4 However, since |-x| = |x| the reflection has no effect.

*September 22, 2016*

**Math**

48,136.47 / 7

*September 22, 2016*

**Math**

40 + 32.60*8

*September 22, 2016*

**geometry incomplete**

no information on the relative placements of the points.

*September 22, 2016*

**Msth**

300+300

*September 22, 2016*

**taxation**

no, it isn't.

*September 22, 2016*

**Math**

1in : 8ft = 1in : 96in = 1:96

*September 22, 2016*

**Algebra**

oops. Forgot to multiply the 4

*September 22, 2016*

**Math**

you have (almost) listed them in order of distance from zero, but smallest means farthest to the left. And even then, 2.4 is closer than 2 1/2

*September 22, 2016*

**Algebra**

by the time you get to algebra, you should know about fractions ... -2x+1/3y=4 -2(-3) + 1/3 y = 4 6 + y/3 = 4 y/3 = -2 y = -6

*September 22, 2016*

**Math (Plz Help ASAP)**

-7 -7(10*60)

*September 22, 2016*

**math**

the difference is 25 km/hr so, 25*12 km

*September 22, 2016*

**Math**

sloppy use of the = signs, there.

*September 22, 2016*

**Algebra**

|n-0| < 6

*September 22, 2016*

**Math**

well, y = 6x-12 plug and chug 6(-3)-12 = -30 ...

*September 22, 2016*

**PHYSICS**

if the acceleration is in the same direction as the velocity, the object speeds up. Otherwise, the acceleration opposes the velocity, so it slows down.

*September 22, 2016*

**Math**

since ln8 = 3ln2 is just a number, you have ∫(2x^2 ln8)dx = ∫2x^2*3ln2 dx = 6ln2∫x^2 dx = 2ln2 x^3 = ln4 x^3 + C Maybe you had a typo, I'm guessing... If so, recall how to do integration by parts: ∫x lnx dx u = lnx du = 1/x dx dv = x dx v = 1...

*September 22, 2016*

**Physical Science/ Chemistry**

reading down the column, they become more reactive.

*September 22, 2016*

**Math**

so, what two numbers add to 9 and one is twice the other? Come on - there aren't that many pairs that add to 9.

*September 22, 2016*

**Math**

x = amt at 4% x-2000 = amt at 5% Now just compare the interest: .05(x-2000) = .75*.04x

*September 22, 2016*

**MATH**

#1A is correct, but it is not scientific notation for the value. #2B is also correct, but not S.N. #3 is 0.593 x 10^4 But, to make it S.N., you need to have 5.93 x 10^3 #4 5.2 x 10^8 / 25 = 0.208 x 10^8 That is 2.08x10^7 Looks like you need some serious review on how to move ...

*September 22, 2016*

**Physics**

v(t) = Vo + at = 85 - 13t It stops when v=0.

*September 22, 2016*

**Algebra**

stop guessing and start working 1/r * s = s/r, so p=s/r + d p-d = s/r Now what do you think?

*September 22, 2016*

**maths**

depends on the value of y. But, since 12y-12 = 12(y-1) it is certainly not prime.

*September 22, 2016*

**Math**

2.3(4.5-9.6)+3.1 = 2.3(-5.1)+3.1 = -11.73+3.1 = -8.63 you are correct. If your input on the calculator is as accurate as your typing here, it is no surprise that is sometimes wrong...

*September 22, 2016*

**Algebra**

the slope of the perpendicular line is -1/7 So, knowing that the line through (h,k) with slope m is y-k = m(x-h) what do you think?

*September 22, 2016*

**Computing**

I think you mean virtual memory. If so, just google it for many discussions.

*September 22, 2016*

**Math**

incorrect writing as a ratio is just one way of expressing rational numbers. Terminating or repeating decimals is another way.

*September 22, 2016*

**Math**

sorry - you wanted the bearing of Q from X. Just subtract 180°.

*September 22, 2016*

**Math**

since Q to P is 140°, P to Q is 320° P to X is 315°, so angle QPX is 5° using the law of cosines, |QX|^2 = 36^2 + 55^2 - 2*36*55*cos5° = 376.1 So, |QX| = 19.39 km 55^2 = 19.39^2 + 36^2 - 2*19.39*36*cosQ So, Q = 165.7° The bearing of X from Q is thus 140...

*September 22, 2016*

**Physics**

it stops going up when v=0. So, since v = 15 - 9.8t v=0 at t=1.53 So, at t=2.5 it is coming back down: http://www.wolframalpha.com/input/?i=15t+-+4.9t%5E2

*September 22, 2016*

**Physics**

t is 2.5 Vi is 15 m/s up a = -9.8 m/s^2 up (or, 9.8 m/s^2 down) d = Vi * t + a/2 t^2 = 15*2.5 - 4.9 * 2.5^2 = 6.875 m Vf is Vi + at = 15 - 9.8 t^2 (though it does not matter for this question)

*September 22, 2016*

**Math**

x = 2 A = {2}

*September 22, 2016*

**Math - eh?**

{x: x 3x=6} ?? Do you mean {x: 3x=6} ?? Then you ask Does A? Does A what? However, you are correct in saying that {2} is not 2

*September 22, 2016*

**Computer science**

https://en.wikipedia.org/wiki/Virtual_memory

*September 22, 2016*

**math**

(72+84+90)/6 + 90/2 = 86

*September 22, 2016*

**math**

also check out the way the coefficients are sums of subsets of the roots: http://mathforum.org/library/drmath/view/61024.html

*September 22, 2016*

**Mathematics**

list a few how far apart is each from its neighbor?

*September 22, 2016*

**math**

think of the factors of 18 which two differ by 3?

*September 22, 2016*

**Algebra**

x = x/3 + 8 + 52

*September 22, 2016*

**Math**

(1 hr 54 sec) * 7 And yet, I suspect you meant 1 hr 54 min.

*September 22, 2016*

**Algebra**

900/(300+250) hours later

*September 22, 2016*

**Math**

6:8:15 * 7/5 = 42/5 : 56/5 : 21

*September 22, 2016*

**calculus**

x^2+y^2 = 10^2 so, when x=6, y=8 2x dx/dt + 2y dy/dt = 0 Now just plug in your values to find dx/dt

*September 22, 2016*

**math**

14250 * 1.02^3

*September 22, 2016*

**United States History**

thank you

*September 22, 2016*