# Posts by STEVE

Total # Posts: 51,234

MATH
there are 20 students. So, the chance of getting the two freshmen is 2/20 * 1/19 = 1/190 This just selection without replacement.

Precalculus
the only constant I see is -1/5 I guess that make the power clear, eh?

I'll let bob handle the physics. You need to proofread your post this time -- get rid of the sloppy typos and finish the question.

science URGENT!!
hello. amplitude is wave height...

science URGENT!!
wave height is amplitude. and it still does not affect the frequency or the speed!

Science
F = ma, so a = -144/15 = -9.6 m/s^2 75 mi/hr = 33.53 m/s v = Vo + at = 33.53 - 9.6t v=0 at t=3.49 So, it will take 1.6 + 3.49 = 5.09 seconds to stop No deceleration occurs during the first 1.6 seconds, so the distance is s = 33.53*5.09 - 4.9*3.49^2 = 110.99 m

Science. HELP!!
not at all. The speed of light does not change because of the color. The speed of sound does not change because the pitch changes.

Math
The first step is to remove the parentheses. Then what do you have?

SCIENCE
The key to this is to come up with the equation of motion. If you review the relevant section, you will easily see that h(t) = 70+40t-4.9t^2 v(t) = 40-9.8t Now just apply your skills from Algebra I to find the vertex and find h(t)=70 and v(10)

Math1
just as the last one, 50=7*7+1

Math1
yep, it's a trinomial. If you want to factor it, recall that 15 = 2*7+1

math
without parentheses, exponents are done first. Remember PEMDAS? Parentheses, exponents, mult/div, add/sub So, -4^2 is evaluated as -(4^2) If you want +16, then that is (-4)^2

math
8×5-(6+12)÷6 = 37 as for simplifying, it doesn't get much simpler than 37 ...

Science, Physics
sinx(cosx-sinx) ---------------------------------- sinx(cosx+sinx)(cosx-sinx)

Science, Physics
sinx(cosx-sinx) ----------------------------- sinx(cosx+sinx)(cosx-sinx)

Science, Physics
(e2x)1/x < (x+ex+e2x)1/x < (2e2x)1/x e2 < (x+ex+e2x)1/x < 21/xe2 Now take the limits, and since 21/x-> 1, e2 < (x+ex+e2x)1/x < e2 so (x+ex+e2x)1/x = e2

Science, Physics
(e2x)1/x < (x+ex+e2x)1/x < (2e2x)1/x e2 < (x+ex+e2x)1/x < 21/xe2

Science, Physics
(e2x)1/x < (x+ex+e2x)1/x < (2e2x)1/x e(2 < (x+ex+e2x)1/x < 21/xe21/x

Science, Physics
(e2x)1/x < (x+ex+e2x)1/x < (2e2x)1/x

math
no idea. how much area does a gallon cover?

Math
start by expressing each factor in scientific notation: 1.31x10^5 3x10^-4 Now just multiply as usual.

math
the whole pipe is the sum of its parts, right?

Math
Since you have two values for y, just set them equal to each other: x^2+2x = 3x+20 x^2-x-20 = 0 (x-5)(x+4) = 0 and you're home free...

College Algebra
Once you get to 5=5 you are done. There are infinitely many solutions. If you put the two equations to the same format, they are y = 5x-5 y = 5x-5 They are the same line. Any solution to one of them is also a solution to the other.

Math
a+12d = 27 a+6d = 3(a+d) Now just solve for a and d.

Math
I agree

Maths
you need to learn to use parentheses online to make it clear what you want, since otherwise, multiplication gets done before addition. You meant (cot^2(x)(sec(x)-1))/(1+sin(x))=(sec^2(1-sin(x))/(1+sec(x)) Apply some of your elementary identities: cot^2(sec-1) = (sec-1)/tan^2...

Maths
recall that (a^3-b^3) = (a-b)(a^2+ab+b^2) sin^2+cos^2 = 1 and it all drops right out.

chemistry
for the same reason that any other endothermic reaction is so considered...

Calculus
there are lots of online graphers. You already know what the graph looks like. The critical points are where secx=0 or tanx = 0 The concavity up or down is provided by the sign of y"...

MAth
so, just plug in the numbers, and you should get 129

College Algebra
no, it is actually .05x + .10y + .25z = 7.80 Now solve 'em!

maths steve reiny bob reiny!!! Help
One side is the distance from (3,4) to 2x+y+3=0 The other side is the distance from (3,4) to x-2y-1=0 The area of the rectangle is thus |2*3+1*4+3)/?(2^2+1^2) * |1*3-2*4-1|/?(1^2+2^2) = 13

Calculus
more like dy/(1+y) = x dx ln(1+y) = x^2/2 1+y = c e^(x^2/2) y = c e^(x^2/2) - 1

Physics

Pre calc
so, why don't you show us how you got it? I get in QIII tan? = sin?/cos? = 5/12, so sin? = -5/13 cos? = -12/13 in QIV sin? = -1/?10 cos? = 3/?10 You don't say what you want to do with that, but sin(???) = (-5/13)(3/?10)-(-12/13)(-1/?10) = 21/(13?10)

Calculus

Math
a nominal rate of r compounded n times per year is (1+ r/n)^(nt) So, since you have a 4t there, .01 = r/4, making r=4% (1 + .04/4)^(4t)

Math
3.3*0.006*10 = 0.198 12*0.005*200 = 12 .198/12 = 0.0165 = 1.65x10^-2

Math
ok, so we have a circle and a tangent. A tangent to the circle will always be perpendicular to a line through the center. Now what? Ever hear of a space bar?

Math
(3.25*8)x10^(-22+3) = 26x10^-19 = 2.6x10^-18

pre calc
what are all those sin() stuff still hanging around? The final expression should just be a bunch of fractions. tan(? + ?); cos(?) = ? 1/3 ? in Quadrant III, sin(?) = 1/4 ? in Quadrant II You really need to review the signs of the trig functions in the various quadrants. In ...

pre calc
me either. why don't you show your work? I've done several already; your turn. I'm sure we can pinpoint where you go astray.

Pre calc
Funny - you and Ruth need to compare notes ... in QI sin? = 5/13 cos? = 12/13 in QII sin? = 1/?5 cos? = -2/?5 sin(?+?) = (5/13)(-2/?5)+(12/13)(1/?5) = 2/(13?5)

Pre calc
Better check my math, then. Also, maybe they don't want the radical in the denominator.

Pre calc
in QIII sin? = -5/13 cos? = -12/13 in QIV sin? = -1/?10 cos? = 3/?10 sin(? ? ?) = (-5/13)(3/?10)-(-12/13)(3/?10) = 21/(13?10)

Math - Calc
You forgot the chain rule. The result is (x^2)^(x^2) * 2x if f(x)=?[1,u] t^t dt and u = u(x) then f'(x) = f(u) * du/dx

Math
well, 141 is 11/12 std above the mean...

If you want h'(x), then that would be [cos(sin^3(x))+sin(x)]*cos(x)

Math - Calculus
((3x+2)/(3x-5))*3 - ((6x+2)/(6x-5))*6

statiictis
So, you want 4 of each kind. Pick any set of 4 from each kind, and then there will be 12! ways to play them. 21C4 * 13C4 * 25C4 * 12! = 2.593*10^19

Calculus
((1/2)x^2-1)^8

math
It's easier if you rewrite it as u = 1/x^4 u^2-u+1 = u^2-u+1/4 + 3/4 = (u - 1/2)^2 + 3/4 = (1/x^4 - 1/2)^2 + 3/4

Math
If all the angles are in QI, then sinA = 4/5 cosA = 3/5 sinB = 12/13 cosB = 5/13 now just use the difference formula

Science! NEED HELP URGENT
none. wavelength and velocity are related, but not amplitude. Now, if you're talking about something like a water wave, where water molecules are moving up and down, then of course, amplitude is related to the velocity of the moving particles.

Geometry
102lb * 0.45kg/lb * 2.5mg/kg = 114.75 mg

English
I think google is very helpful for these idioms. You can get various definitions and explanations.

Math
Maybe if you explain what you mean by a road a pound we can work it out. However, the perimeter of the drawing is 16 inches, and 16*5 = 80 so ...

Language Arts
ever see a cold, dreary, misty winter day? (between dawn and dusk, both the boundaries of the dark of night)

trigonomenty
Try this. http://www.cut-the-knot.org/pythagoras/cos36.shtml

math
plug in 3 for p: 3 = 14-2q

Math
distance = speed * time so just crank it out

Math
well, what numbers multiply to 40? example: 8*5 = 40 so, -8*5 = -40 8 * -5 = -40 Now, pick any other factors of 40. As long as an odd number of them are negative, the result is -40 2(-2)(-2)(-5) = -40 -10 * 4 = -40 and so on. Not as hard as it looked, was it?

math
both numbers are close to 2. What's 2+2 ?

Maths
well, he spent 1/4 + 1/3 = 7/12 so, what's left?

College Algebra
correct. Now it's smooth sailing.

Precalculus
so, you couldn't fix it and finish it off? The method was right in front of you ... r = 8sin? - 2cos? r^2 = 8r sin? - 2r cos? x^2+y^2 = 8y-2x That's ok as an equation, but I suspect you want a more standard form, so keep working it, completing the squares: x^2+2x + y^2...

Precalculus
x^2+y^2-6y-8 = 0 r^2 - 6rsin? - 8 = 0

Precalculus
I suspect a typo, but r = 8sin? - 2sin? r = 6sin? r sin? = 6sin^2? y = 6(x^2+y^2)

math
8/2 (2a+7d) = 50 50/2 (2a+49d) = 880 Solve for a and d, and then evaluate a+42d

science
decrease in distance, since F depends on 1/r^2

math
Since the terms of a GP have a common ratio r, (n+2)/(n-4) = (3n+1)/(n+2) If you solve for n, you will get two possible values. Use those to determine the appropriate values of r.

College Algebra
If you want to use elimination, arrange the equations so that x,y,z occur in order, and enter the coefficients into the array here: http://www.gregthatcher.com/Mathematics/GaussJordan.aspx

College Algebra
This one is easier to solve just using substitution: y=3z, so x+3z+z = 50 4.50x + 3(3z) + 4z = 4.38*50 Simplify those to get x + 4z = 50 4.50x + 13z = 219 Now, since x = 50-4z, 4.50(50-4z)+13z = 219 225-18z+13z = 219 5z = 6 z = 1.2 y=3z = 3.6 x=50-4z = 45.2 This makes sense, ...

College Algebra
you don't seem to be reading what is given. If you set up your x,y,z as you did, then x+y+z = 50 y = 3z 4.50x + 3y + 4z = 4.38*50

College Algebra
almost x + y = 5000 3x +7y = 23000

College Algebra
so, x+y=5000

College Algebra
No, 3x+7y = 2300 represents the total money collected. That equation is correct. How many tickets were sold?

College Algebra
Nope. x+y represents the total number of tickets sold. That is not 23000.

College Algebra
You have tried to use the model where they give you the total interest earned. This one does not do that. Instead, if you read what was written, your second equation must be .08y = 32 + 2*.06x

Maths
hint: If 3|n^2 then 3|n*n

Algebra
Huh? -16*3^2+60*3+6 = 42

Math
the vertical mast makes a right angle with the level ground, right?

Math
50/AC = tan28° 50/AB = tan44° Now use the law of cosines to find BC

Math
sin^-1 (4x^4+x^2) = 1/6 pi take sine of both sides: 4x^4+x^2 = 1/2 8x^4+2x^1-1 = 0 (4x^2-1)(2x^2+1) = 0 ...

Calculus
If G(t) = ?g(t) dt then ?[3,x] t^5 dt = G(x)-f(3) so, f'(x) = x^5 ...

algebra
add up the amount of acid present: .40x + .10(540-x) = .20(540)

math algebra three system equation
If you want to see the details of elimination, a good place to go is http://www.gregthatcher.com/Mathematics/GaussJordan.aspx

Word problem
if 16 of each, total is 480 Each quarter replaced with a nickel drops the total by 20. So, to lose 60 cents, replace 3 quarters with nickels. 19 nickels, 13 quarters 19*5+13*25 = 420 Too bad you won't show your work ...

mechanies
By the law of cosines, if the angle between a and b is ?, |a+b|^2 = |a|^2 + |b|^2 - 2|a||b|cos(180-?) So, |a+b|^2 = |a|^2 + |b|^2 + 2a•b

Word problem
or, say she has equal amounts of coins: 11 nickels, 11 dimes. The total amount is 11*5+11*10 = 165 Yet we are told that she has 175. Each time we replace a nickel with a dime, we get 5 more cents. So, to get those extra 10 cents, we need to replace 2 nickels with dimes: 9 ...

MATH HELP PLS
19. Mr. Green teaches band, choir, and math. This year, he has 57 students that take at least one of his classes. He teaches band to 25 students. There are 48 students who take either band or choir or both. There are 9 students who take both math and choir with Mr. Green. Use ...

MATH<<<<<
I need help, how do you find the mean median mode and range?

MATH<<<<<
What are the mean, median, mode and range of the data set given the altitude of lakes in feet: –12, –9, –14, –39, –49, –49, –18, and –43?

math
49+51

geometry
the angle bisector splits a corner into two 45° angles. That means that the rectangle is 10x20.

math
note that ?BOC is a right triangle, since the diagonals are perpendicular.

math
so, did you do it? Start by labeling the time axis 1..2..3....10

Math
8gal/340mi * \$4.00/gal = \$0.0941/mi 7gal/350mi * \$4.00/gal = \$0.0800/mi

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