# Posts by Steve

Total # Posts: 52,318

math
use the law of sines. The distance z is z/sin91 = 4/sin44

MMATH08
well, since the 10 tiles cover the floor, each must have area 8000/10 = 800m^2 so, the tiles must have side length 20?2 unfortunately, you cannot cover a square floor with 10 square tiles, since 10 is not a perfect square.

Msth
just subtract the picture area from the total: (20)(30)-(20-10)(30-10)

Geometry
(x,y) -> (x-4,y-8)

Kaylee - banned
lim n->? of n ? (5+k(2/n))10(2/n) k=1

Probability and Statistics
If you plug some of your numbers in at this web site, I think you'll soon see how things work. http://davidmlane.com/hyperstat/z_table.html

Trig
not bad, but why did you subtract? d/dx (x+8)^(1/2) = (1/2)(x+8)^(-1/2) your derivative is good, except for that.

Math
to find r, note that a9/a4 = r^5 then use that to find a1

math
nope. P(heads) = 1/2 P(n<5) = 4/6 = 2/3 so, P(heads, n<5) = 1/2 * 2/3 = 1/3

Algebra
well, I guess you know the answer, then, right?

Algebra
none. You need two factors of 24 which differ by 1. Check for typos 1,24 gives 23q 2,12 gives 10q 3,8 gives 5q 4,6 gives 2q

algebra
2^(3/4) ----------- = 2^(3/4 - 1/2) = 2^(1/4) 2^(1/2)

Music
I guess you have picked the best answer Unlike a piano, whose strings are hit with hammers, and whose volume can vary (piano-forte), a harpsichord's strings are plucked (like a harp's) and always play at the same volume. Listen to some recordings and it's easy to ...

English
could is the past tense of can I can swim well. Yesterday I could swim well. Then there are the conditional and perfect uses, but maybe you're not after those.

physics
watch the units wavelength(m) = speed(m/s) / frequency(1/s)

Math (Calculus II) (Partial Fraction Decomposition
So, you have two polynomials, which are identical. That means all the coefficients on both sides must be the same. That is, x = B(x^2+a^2)(x-a) + C(x+a)(x^2+a^2) + (Dx+E)(x+a)(x-a) = B(x^3-ax^2+a^2x-a^3) + C(x^3+ax^2+a^2x+a^3) + D(x^3-a^2x) + E(x^2-a^2) = (B+C+D)x^3 + (-aB+aC+...

Math
They all look ok to me, except #2. Recall that the slope is ?y/?x pick any two pairs and see what you get #3. Note that y increases by 5 for each step. You could not possibly have tried 3x+6 on more than one pair. #5. Again, you clearly only tried n=1.

Math
No. There were 10 tosses. 8 of them showed at least one H So, P = 8/10 = 0.8

Math
you have it exactly backwards. 0.2 is the probability that NO heads showed.

Physical Science
well, 1/16 = 1/2^4 so it takes 4 half-lives

Math
16

Math
6":18' = 1:36

math - try again
fix the typos and post it again.

math
each man does 1/(24x) in a day each woman does 1/(32(x+8)) in a day so, 15/(24x) ------------ = 3/1 12/(32(x+8)) yes, x=10

science

math
42

Math
well, tan? = 180/215

Algebra 2
that's right.

Algebra 2
nope. If it has a maximum, then the graph turns back on itself, so it fails the horizontal-line test.

Geometry
Since they share a common diagonal BD, they are the same rectangle.

Algebra 2
f?g = f(g) = g^2-5g+6 = (x+3)^2-5(x+3)+6 = x^2+x

Pre Algebra
7^5 * 7^6 = 7*7*7*7*7 * 7*7*7*7*7*7 = 7^11 all 7's, no 49's

Pre Algebra
nope 7^5 * 7^6 = 7^(5+6) = 7^11 Better review the rules of exponents. The base does not change: a^m * a^n = a^(m+n) NOT (a^2)^(m+n)

Algebra 2
f(x)-g(x) = (x^2+2x-6)-(3x^2-5x-7) = x^2+2x-6-3x^2+5x+7 = -2x^2+7x+1 watch those minus signs when subtracting!

Math Graphing
http://www.wolframalpha.com/input/?i=y%3D+1%2F5x+-+2

Math
you are

Trig help
A is correct

for the integral, there are two ways. shells of thickness dx: v = ?[0,2] 2?rh dx where r = 5-x and h=x-x^2/2 v = ?[0,2] 2?(5-x)(x-x^2/2) dx = 16?/3 discs (washers) of thickness dy: v = ?[0,2] ?(R^2-r^2) dy where R=5-y and r=5-?(2y) v = ?[0,2] ?((5-y)^2-(5-?(2y))^2) dy = 16?/3 ...

maths
correct

maths
If you let u = 4x^2 v = 3-x then you have y = (u/v)^3 y' = 3(u/v)^2 (u/v)' = 3(u/v)^2 ((u'v-uv')/v^2) = 192x^5(6-x) / (3-x)^4

maths
All the steps in your work are correct.

maths - try again
all that duplicated text is impossible to parse. Try typing it in, rather than copy/pasting. Use t^2 for t squared

Trig help
C is correct

Algebra
come on. For #5, you have 5x-20y=60 5x-20y=60 They are the same equation. So, any solution to one is also a solution to the other. Try a similar comparison for #6 and just think about what it means.

math help?!
correct

algebra
15 < 5x

Science
correct

AMth
64/256 = 1/4 I don't see any matches

calculus
The sequence can be rearranged as 1/3, 1/4, 1/5, 1/6, ... ....1, 1/2, 1/3, 1/4, ... so, the terms converge to zero The sum, however, will come close to twice the sum of the harmonic series, which diverges.

calculus
2+3+4+... = n(n+1)/2 - 1 So, if N = n(n+1)/2 - 1, you know that the Nth term is 4, and the n+1st term is 0 So, while the number of zeros is infinitely many more than the number of 4's, the terms do not converge to either 4 or 0.

calculus
by this time you should know that exponentials always overcome polynomials.

calculus
since cos(x) oscillates between 1 and -1, the sequence does not converge. As n/8 comes arbitrarily close to multiples of pi, cos(n/8) will get close to 1 or -1.

calculus
since the terms are just basically 1/?n the sequence converges to 0

precalculus
the circumference of the wheel is just 2pi*r

Geometry
clearly, 10+1/2(8.7x6.7)=39.145 But, unless you provide some more information about B,P,I and their relation to the pyramid, it's hard to say whether that is really S.

Math
Since you give no indication of a horizontal speed, I don't see how just jumping up and down will get him over the building. However, his maximum height will be at x=200/32=6.25, so plug that in and see whether it is high enough. I suspect that you meant the f(x) gives the...

History
Have a good week.

History
It does because of all the lost jobs in the auto industry and sub firms supporting them. Just wanted to check for my grandson. thank you

History
Which of the following region's populations grew the slowest during the second half of the 1900's?) The Midwest The Southwest The Southeast The West Coast my answer is the midwest

calculus
If she walked x km, then since time = distance/speed, x/3 + (8-x)/7 = 2

Math
not quite a8 = a+7d = -3+7(-4) = -31

Calculus
draw a diagram. It is clear that tan? = x/25 so sec^2? d?/dt = 1/25 dx/dt 1.0353 d?/dt = 0.04 * 1.5 d?/dt = .057 rad/s d?/dt is constant, and since there are 2? radians in one revolution, the period is 2?/.057 = 110 seconds Better check my math; 2 minutes/rev seems like a long...

Trigonometry
anything which makes 1-sinx=0

Math
Just write the facts as equations: b = g+p p = 12 g = p/2 Now find b+g+p

Algebra/ Geometry
?(1.5r)^2 = ?r^2 + 100 9/4 ?r^2 = ?r^2 + 100 5/4 ?r^2 = 100 r^2 = 80/? r = 4?(5/?) so, the original circumference is c = 2?r = 8?(5?)

Homework Dump
If you have no ideas on any of these, you clearly have not studied the material yet. When you have some suggested solutions, we can check your work.

math
just change all the signs of y. f(x) = -2/3x+2 --> -f(x) = -(-2/3x+2) and so forth

Geometry
just as the volume of a rectangular brick is length*width*height, it is also base*height, with the base having area B=length*width, so v = Bh A triangular prism also has volume Bh, where B is the area of the triangular base. try googling prisms and volumes for more discussions...

Geometry
well, you haven't said which two dimensions constitute the triangular base. If the triangle has base=15 and height=12, then its area is 90. Then the volume is 90*7 = 630

Geometry
v = Bh you know how to figure B -- it's just the area of the triangle, so ...

math
So, the total man-days worked in the 14 days is 2*24 + 2*28 + 10*22 = 324 Without knowing how much total work is needed, there's no way to tell how many more days it will take.

Geometry
Assuming P is between A and B, then (6+2)/(-2-x) = 3/2 x = -22/3 If B is between A and P, or A is between P and B, other conditions apply, as I'm sure you can figure out.

Geometry
The area is bounded by 1/4 of the circle with center at (-8,8) and radius 8. So, it's just r^2 - 1/4 (pi r^2) 64-(1/4)pi*8^2 = 64-16pi

Math
-60 is included so, which way is to the right? greater or less?

Math
you've been on this site long enough to know that diagrams don't make it here.

Trigonometry
the boat has traveled 5 miles. So, if the distance to shore is d, d tan70° - d tan63° = 5

Trigonometry
42m

Algebra
I assume you are studying the distributive law. So, 3*(x-y) = 3*x - 3*y or, 3x-3y do the other in like wise.

Math
speed * time = 500

math
A = P(1+r)^t

maths
jut note that h/42 = tan 36°

physics
The half-life is 3.82 days That means that every time 3.82 days have passed, 1/2 of it is gone. So, starting with 400 nuclei, after 2 days there will be 400(1/2)^(2/3.82) = 278

Math
.06x = .20*6

algebra 1
(3x-6)(x+4)

Math
since 1m = 3.28 ft, the area is 4*5 * 3.28^2 = 215.17 ft^2

math
ar^2 = 54 ar^6 = 1/54 r^4 = 1/54^2 r^2 = 1/54 a = 54^2 T5 = ar^4 = 54^2 * 1/54^2 = 1 The sequence is 54^2, 54/?54, 54, ?54, 1, 1/?54, 1/54 ...

Math
the marked price should have been .95p, or 19*.05p = 19*4.20 = 79.80

Math
I assume that "70percents/dozen" means "70 cents per dozen." If so, he sold 2400 = 200 dozen at that price. So, his % profit is ((200*.70)-100)/100 = 40%

Math
since volume scales as the cube of the linear ratio, the small cone has 1/27 the volume of the whole cone. So, the parts' volumes are 5(1/27) and 5(26/27)

Math
10/2 (2a+9d) = 20/2 (2a+19d) 20a+90d = 40a+380d 20a+290d = 0 2a+29d = 0 S30 = 30/2 (2a+29d) = 0

speed
distance = speed * time, so if Tom's speed is s, his distance was 4s. For Jerry, (4/5)(4s) = 4(s-2) solve for s, and then you can get the distance: 4s

science (physics)
assuming constant acceleration from position s(0)=0, s(t) = vt + 1/2 at^2 So, we have s(5)-s(4) = 10 s(10)-s(9) = 30 now just plug in the numbers and you get 5v+25(a/2)-(4v+16(a/2)) = 10 10v+100(a/2)-(9v+81(a/2)) = 30 Now just solve for a and v.

Geometry
Take a look at the figure here, and plug in your numbers: http://mathcentral.uregina.ca/QQ/database/QQ.09.07/h/astrogirl1.html

Math
12x+30*900 = 42*875

Math
1.12c = 6 + 0.88c

math
well, x = 5n y = 2n-1 Now just get rid of n.

math
x + 2(60-x) = 92

math
so, did you graph it? Where does the line cross the x-axis?

math
t = 7x t+5 = 4(x+5) so, 7x+5 = 4(x+5)

College Algebra
I = k/d^2 so, Id^2 = k is constant So, find d such that 40d^2 = 90*5^2 and subtract 5