# Posts by STEVE

Total # Posts: 51,753

**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

**multivariate calculus**

I've done a couple of these for you now. Where do you get stuck? What do you have so far? Doing the partials can be tedious, but not difficult. You can get some help here, for example, to verify your work: http://www.wolframalpha.com/input/?i=d%5E2%2Fdx%5E2+ln(x%5E2+%2B+y%...

**Math**

since the height:shadow ratio is the same, 64/30 = h/25

**math**

well, 2+5=7 so, what do you think? More algebraically, if there are 2x dogs and 5x cats, 2x+5x = 14 solve for x, and then you can tell how many animals are there.

**Math**

There are 4 rectangular faces, each 7x13

**math**

geez - impatient much?

**Science**

mine, too

**Science**

well 1 million would provide 1000000/24000 = 41.7 mg

**Science**

so, how many nematocysts are there? divide by 24000 to see how many grams

**Science**

B & D look good to me

**math**

Can't say I care much for your text formatting. Since you seem to be dealing with fractions, I assume you meant to say R = 3/x + 9/y So, just plug in your numbers and solve for x: 7 = 3/x + 9/6 If I got the function wrong, just fix it and plug in the numbers to get ready ...

**math**

just subtract the picture from the total area: (40+15)(50+15) - 40*50

**Calculus**

well since the fraction approaches 1/0, clearly it will approach either +? or -? So, just check the denominator to see whether it is positive or negative. a) x->2+ means x > 2. So, x^2 > 4 and the limit is +? similarly for the others.

**Math**

m = 3d m-5 + d-5 = 50

**Math**

a - x/2 = 12 a + x/2 = 2x x = 2x-12 x = 12 finish it off

**Math**

j+k+b = 390 j = 5b k = 3/4 j now just solve for k.

**Math (Integrals) (Volume of Revolution Setup)**

looks good to me

**Math Tangent Graph**

the graph of tan(x) goes through (0,0) and has asymptotes at -?/2 and ?/2, for a period of ?. This graph also goes through (0,0) but its asymptote is at -?/6, for a period of ?/3. So, it is the graph of tan(3x) Or, note that instead of a single period in [-?,0] it has 3 periods.

**Algebra**

You have some funky formatting there. I read it as f(x) = 8*3^(x-2)+2 but it doesn't really matter what f(x) is. Stretching by a factor 3 just means that g(x) = 3*f(x)

**physics**

scroll down a bit here, and you can figure it out. https://en.wikipedia.org/wiki/Trajectory

**Math**

surely you can see that 0 represents the year Gabe was born. since Gabe was 14 in 2002, you can easily figure out the year that he was born.

**Math**

correct

**Math**

geez - just get out a pencil and draw the number line. Start at 0. Move right 10 and then left 11 where are you?

**maths**

well, there are 7 1/2 circles. They represent 15 goals, so 15/(7 1/2) = ?

**Algebra (Ms.Sue!!)**

if you add 5 to each value, you add 5 to the mean and median. The range is unaffected. if you multiply by 6, the mean and median get multiplied by 6, and so does the range. Review these topics in your text or online. The definition of these items will show how they are ...

**Math**

well, .22x = 209

**Math**

quite a difference in your posts. 2x * 9x^(y^9)) = 18x^(y^9+1) Now, taking the derivative of u^v is a combination of d/dx a^v = lna a^v dv/dx d/dx u^n = n u^(n-1) du/dx d/dx u^v = v u^(v-1) u' + lnu u^v v' Since we have u=x, and v=y^9+1, taking d/dx, we get (y^9+1) x^(...

**Calculus**

why all those messy words? You appear to be saying f(x) = 3 for -3 <= x < 0 -x+3 for 0 <= x <= 6 -3 for 6 < x <= 9 g is increasing where f is positive: [-2,0)U(3,6] g(x) = ?[-2,0] 3 dt + ?[0,x] -t+3 dt = 6 + (-x^2/2 + 3x)+3 for 0<=t<=6

**Physics**

F = ma now just plug in your numbers.

**calculus**

s = ?[0,?] ?((2t)^2+(t cost)^2+(t sint)^2) dt = ?[0,?] ?(4t^2+t^2) dt = ?5/2 ?^2

**Math Probability**

I agree

**geometry hhhheeeelllllpppppp**

there are two triangular bases of area (1/2)*3*2.6 there are three rectangular faces. One has area 12*3 the other two have length 12, but we do not know the other two sides of the triangle...

**calculus**

well, you have tanz = r^2 tan2? z = arctan(r^2 tan2?) ?z/?r = (2r tan2?)/((r^2 tan2?)^2+1) ?z/?? = (2r^2 sec^2(2?))/((r^2 tan2?)^2+1) the second partials get a bit messy, but you can get them here: http://www.wolframalpha.com/input/?i=d%5E2%2Fdr%5E2+arctan(r%5E2+tan2%CE%B8) ...

**calculus**

just crank it out ?u/?x = 2x/(x^2+y^2) ?u/?y = 2y/(x^2+y^2 ?v/?x = -2y/(x^2+y^2) ?v/?y = 2x/(x^2+y^2

**MATH**

the link is missing a domain name, such as http://pictures.com/...

**math**

16 2/3% = 1/6 1/6 * 9 = ...

**math**

12* 5/3 = 5 * 12/3 = ...

**maths**

see your previous posts and work this the same way. We can check your answer.

**maths**

see your previous two posts and work this the same way. We can check your answer.

**maths**

this is the same as cos30/sin30 + sin30*cot30 = cot30(1+sin30) = ?3 (1+1/2) = 3?3/2

**maths**

These are standard angles, whose functions you would do well to learn Cos45+sin60-tan30 = 1/?2 + ?3/2 - 1/?3 = (3?2 + ?3)/6

**maths**

well, (1+cot²x) = csc²x

**Geometry**

there are many possible line segments drawn from a to bc

**Maths**

301 They all leave remainder

**Algebra**

what's the trouble? They say S = ?(30fL) just plug in your numbers and solve for L

**Algebra**

If the painting has length x and height y, and the frame has width w, then we have x+2w = 10 y+2w = 8 x^2+y^2 = 100 Now just solve for w

**Math**

I get 104. What do you get?

**Math**

try using <= for "less than or equal" "under 12" means "less than 12" so, what do you think?

**Math**

n > 130-87

**Math Check! #3**

yeah, but how does that relate to choosing 4 players from a group of 8?

**Math Check! #3**

Hmmm. How did you get 336? This is just a "choose 4 of 8" combination. 336 = P(8,3) How does that relate to this problem. I suspect you just guessed.

**maths**

not sure what -< and +< mean

**Math**

2/(3/4) = x/30

**Algebra2**

Thank you

**Algebra2**

The water level varies from 12 inches at low tide to 52 inches at high tide. Low tide occurs at 9:15 am. High tide occurs at 3:30 pm. What is a cosine function that models the variation in inches above and below the water level as a function of time and hours since 9:15 am? ...

**Geometry**

correct

**Algebra2**

The function f(theta) and g (theta) are sine functions where f(0)=g(0)=0. The amplitude of f (theta) is twice the amplitude of g(theta). The period of f(theta) is one-half the period of g(theta). If g (theta) has a period of 2pi and fpi/4=4. Write the function rule for g(theta...

**MATH**

since you give no indications of any side lengths, it's kinda hard for us to say, right? and besides, area is in cm^2, dontcha know

**Algebra2**

thank you

**Algebra2**

for which value of theta is tan theta equal to sin theta? My answer is pi

**math**

42.75*1.18

**Math**

if you mean the angle is 20°, then the radius r of the circle can be found using' 5/r = sin10° Now you know r, so you can find the area of the circle...

**chemistry**

how many moles in 5.3g? Molarity is moles/liter

**Math**

since xy=48 for each pair, B is correct.

**Algebra2**

Thank you

**Algebra2**

cos?+1 = 0 cot(?/2) = 0