Tuesday

October 21, 2014

October 21, 2014

Total # Posts: 25,949

**physics**

The swimmer's direction should be the hypotenuse of the diagram. Then, the current makes the resultant velocity perpendicular to the bank. The angle is thus upstream at an angle of arccos(1.5/3.76)=66.5° relative to the bank. That makes the speed relative to the shore...
*August 21, 2014*

**math**

For m minutes, A: 25.00+0.10(m-30) B: 20.00+0.12(m-30) So, just solve for m when A=B The language used for this problem is rather odd. Not at all what I'd expect from a school text.
*August 21, 2014*

**math**

since 7y=28x, y = 4x 6x+4(4x) = 40 22x = 40 x = 20/11 x^2 = 400/121
*August 20, 2014*

**Math**

just subtract his initial loss from the subsequent profit: 1580-415 = ?
*August 20, 2014*

**Algebra**

sounds good. You might also note that for an exponential function y = f(x), log(y) is linear.
*August 20, 2014*

**Geometry - eh?**

Hard to say. Just noting the degrees separating the hands tells nothing about the actual time. And, since you don't specify which hand is at 70 degrees, that's no help either. Want to rethink the question?
*August 20, 2014*

**Math**

If you mean (225-256)^2 that's just (-31)^2 = 961 If you mean 225-256^2 that's -65311
*August 20, 2014*

**Algebra**

easy. Note that y^3 / y^10 = y^3 / y^3*y^7 The y^3 factors cancel, and you are left with 1/y^7 Or, use the rule that in division, you subtract exponents, so y^3/y^10 = y^(3-10) = y^-7 = 1/y^7
*August 20, 2014*

**college algebra**

It's already factored! Want to rephrase the question?
*August 20, 2014*

**maths**

what do meters have to do with anything? If the equation is 3 cos x = 25x, that's one thing. If not, fix the equation, but leave the m^2 out of it.
*August 20, 2014*

**MATHH**

The slope of the line joining those two points is (4+7)/(3-2) = 11 But, you are supposed to find the slope of any perpendicular line. That is -1/11.
*August 20, 2014*

**math**

1. reflect through the x-axis 2. reflect through (0,0) 3. a translation, but you are missing a sign.
*August 20, 2014*

**math**

You have a/b = 4/5 a/c = 6/11 You want b/c = (b/a)/(c/a) = b/a * a/c = 5/4 * 6/11 = 30/44 = 15/22
*August 20, 2014*

**math**

B gains 100 yards every minute. So, after 10 minutes, B has lapped A once. C gains 100 yards on B every minute, so after 10 minutes C has lapped B. Thus, after 10 minutes, A has gone 7 laps, B has gone 8 laps, C has gone 9 laps, and all are even again.
*August 20, 2014*

**Math**

-8 is less than any of them. All the negatives come first. The || values are all positive. So, (C) is correct
*August 20, 2014*

**Geometry**

In an equilateral triangle, the median is the same as the altitude. If the side is s, the median is √3/2 s. Each median extends from a vertex to the midpoint of the opposite side.
*August 20, 2014*

**algebra**

I get this far √a-√b = √18-√6 and have trouble figuring out what "nd multiply root5" means. How about filling in the rest using math symbols?
*August 20, 2014*

**math**

None are. They are, however, supplementary.
*August 20, 2014*

**Maths**

that would be 645.7/8 Drag out your calculator of choice to evaluate that quotient.
*August 20, 2014*

**Algebra**

D = 1.2√H Now just plug in H=12000
*August 20, 2014*

**Trigonometry**

Looks like time to review the basic trig functions. It always helps to draw a diagram. (1) 12.75/x = sin 48° (2) sin x = 3.1/9.4 (3) 16/x = tan 9°
*August 20, 2014*

**Math**

mi/hr * 1hr/60min * 1min/60sec * 5280ft/mi Note that the units all cancel out, leaving ft/sec Actually all of the factors will work, if you divide by 1mi/5280ft. However, since one usually wants to multiply, I'd say (d) would not be used.
*August 19, 2014*

**math**

y = x^3 All of the odd powers look basically the same as x^3. Play around at wolframalpha.com to see.
*August 19, 2014*

**math**

hmmm. Is it 4? Is 4^2 = 36? Does 4 have 3 as a factor? Better read what I wrote, and this time pay attention.
*August 19, 2014*

**math**

I'd make that 6, since 81 = 3^4. p^2 must have some powers of 3 in it, else GCF(p^2,81) = 1. GCF(36,81) = 9 9 would be better, but we needed an even integer.
*August 19, 2014*

**English**

none that I know of, but there are plenty which will correct your spelling of "grammar."
*August 19, 2014*

**Physical Science**

The airspeed is the speed relative to still air. In the absence of other factors, the airspeed is the same as the ground speed. If the wind is blowing, the wind velocity must be added to the bird's velocity in still air (airspeed), to get the velocity relative to the ...
*August 19, 2014*

**physics**

total distance: 108+42 = 150km total time: 6hr avg speed: 150km/6hr = 25 km/hr
*August 19, 2014*

**math STEVE**

you could have appended the correction to the original post. Anyway, 783-500 = 283 Apparently he makes no commission on the first $100. Assuming that, he makes 0% on 100 = 0.00 5% on 400 = 20.00 10% on 283 = 28.30 Total = 48.30 If I made a mistake on the first $100, make the ...
*August 19, 2014*

**math**

read it. The last sentence makes no sense.
*August 19, 2014*

**math**

#2. Assuming all the rest tried out for pitcher, then we have 1/8 + 1/3 + 1/4 = 17/24 So, the remaining 7/24 must have tried out for pitcher. #1 is garbled.
*August 19, 2014*

**math**

I did it this way 20*34 = 680 (total of all 20 numbers) 4*45 = 180 (total of the 4 numbers with mean 45) 680-180 = 500 (missing total, due to the other 16 numbers) 500/16 = 31.25 Your final answer is so huge it should have been a tipoff. The mean of the other 16 should have ...
*August 19, 2014*

**math**

6(y-7)-6 = 6y-48
*August 19, 2014*

**math**

no. my typo of 41 is a boo-boo, but your answer is correct. You correctly answered the question that was asked.
*August 19, 2014*

**math**

looks good. Does it work? Jack is 45 5 years ago, he was 41 40 = 46-6 OK
*August 19, 2014*

**Science - go with DrBob**

Dang. I forgot about the molecules, not atoms.
*August 19, 2014*

**Science**

you know Avogadro's Number, AN=6.023*10^23 Also, 1 mole occupies 22.4L (22400 cm^3) at STP. (a) (50dm^3)/(22400cm^3) * AN = ? (b) (10cm^3)/(22400cm^3) * AN * 19 = ? (because F has 19 nucleons/atom)
*August 19, 2014*

**Math**

(a) note that as x increases by 4, y increases by 2. Then, as x increases by 2, y increases by 1. (b) and (c) work the same way. Starting at the first point, note that the changes in y and x have the same ratio. That is, the slope remains constant, and since the middle point ...
*August 19, 2014*

**Science**

well, they would be nice to know, but the crew of the carrier would presumably include a doctor and weather guy. I'd pick D over A. Modern ships have lots of computers on board, and a knowledge of physics would come in handy in handling the ship.
*August 19, 2014*

**math**

using substitution, 7/y = 31-5/x so y = 7/(31-5/x) = 7x/(31x-5) 7x+5y=29xy y = -7x/(5-29x) 7x + 35x/(31x-5) = 29x * 7x/(31x-5) 7x(31x-5) + 35x = 203x^2 14x^2 = 0 As Damon noted, x=0 is not allowed, so there are no solutions. If you plot the difference between the two functions...
*August 19, 2014*

**math**

looks like (b) to me (a) is distributive
*August 19, 2014*

**math**

assuming both values are -1, even powers of -1 are +1 odd powers are -1 so we have -1 - +1 = -2 Or, you could factor out (-1)^1988 and have (-1)^1988(-1 - 1) = (+1)(-2) = -2
*August 19, 2014*

**quadratic function**

let x be the time since midnight, and y be the water level. We have y(11.75) = 0.46 y(23.50) = 0.46 the vertex is thus (17.625,2.16) Now you have three points, so you can determine the parabola, and you want x where y=1.
*August 19, 2014*

**math**

If the length is x, the width is x-.5 so x(x-0.5)=3 Now just solve for x
*August 19, 2014*

**math**

Hmmm. If you had said three more than twice its width, I'd have immediately said the room was 5x13. But, now we have to use some algebra. w(3w+3) = 65 w = 4.1815 for the perimeter, we want 2(w+3w+3)=39.452
*August 19, 2014*

**algebra**

I'll take a stab at it. As written, it appears to be (-1^2+11^2)(11^2- -7^2) (-1+121)(121- -49) (120)(170) 20400 If we assume the usual carelessness with parentheses, per Damon, then we have ((-1)^2+11^2)(11^2- (-7)^2) (1+121)(121-49) (122)(72) 8784 I can't believe you...
*August 19, 2014*

**statistics**

better check your dairy almanac for stuff like this.
*August 19, 2014*

**Math**

why is google like a search engine?
*August 19, 2014*

**Math**

depends on whom you ask Most say 5 rounds up Some say 5 rounds to the next even digit, so 35 rounds to 40 45 rounds to 40 Better check with your instructor or text to see which answer will get you marked correct.
*August 19, 2014*

**Science**

weight(N) = mass(kg) * 9.81 m/s^2
*August 18, 2014*

**Advanced algebra**

looks discrete to me
*August 18, 2014*

**math**

15*5+2 = 77 15*6+2 = 92 So, only two of them
*August 18, 2014*

**Algebra 2**

midway between the two extremes is (32.85+31.15)/2 = 32.00 So, |x-32.00| <= 0.85
*August 18, 2014*

**Programming**

read amount, months; show_deposit(amount,months); function show_deposit(amount,months) { deposit = amount/months; print deposit; }
*August 18, 2014*

**maths**

Hmmm. you are mixing up price per kg and per cob, with no indication of how many cobs per kg.
*August 18, 2014*

**Maths**

50-y You can easily do stuff like this if you use an actual number, and then study how you solved it. Suppose you had R50 and spent R10. What is the change?
*August 18, 2014*

**Please Help ! Analytic Geometry**

try this solution: http://www.jiskha.com/display.cgi?id=1408162681
*August 18, 2014*

**Algebra**

Not bad, except that 6.5-4 ≠ 1.5
*August 18, 2014*

**Math**

assuming the 2300 included the 15% profit, the value was 2300(0.85) Now divide that by 100 to get the per-share price.
*August 17, 2014*

**Alegbra**

you are correct. To see its graph, type that in at wolframalpha.com
*August 17, 2014*

**math**

assuming the smaller rectangle is enclosed by the larger, we have small rectangle: w(2w-1) large rectangle: (w+2)(2w-1+2) Assuming the shaded region is the difference between the two rectangles, we have (w+2)(2w+1)-w(2w-1) = 86 w = 14 So, the smaller is 14x27, with area=378
*August 17, 2014*

**trig**

since the spring starts at (0,-17), we know that D(t) = -17 e^-at cos(kt) since the period is 1/13, k = 26π and we have D(t) = -17 e^-at cos(26πt) Now, we know that the amplitude has decreased to (16/17)^(t/3) That means that a = -1/3 ln(16/17) = .02, and D(t) = -17 ...
*August 17, 2014*

**geometry**

Of course the 3rd side can be 5 or 9. That just makes an isosceles triangle. So, you want all the numbers n such that 4 < n < 14: 5+6+7+8+9+10+11+12+13 = 81
*August 17, 2014*

**geometry**

as a hint, suppose you joined the two sticks at the end. Now consider rotating the smaller one, from being end-to-end with the larger one, to overlapping it. What's the max and min possible length for the third side? Now list all the integers in that range and add 'em up.
*August 17, 2014*

**geometry - again?**

another of these triangle problems? Have any ideas of your own on this one?
*August 17, 2014*

**physics - Go with Damon**

As usual, go with Damon. He tends to think things through more carefully.
*August 17, 2014*

**physics**

as usual, s = 1/2 at^2 Since g is acting downward, the net acceleration is 32-9.8 = 22.2 m/s^2 upward s = 1/2 * 22.2 * 4.1^2 = 186.6m Actually, the question is poorly worded, since it implies that the net acceleration is 32 m/s^2, even after including the effects of gravity. ...
*August 17, 2014*

**math**

more formally, for the purposes of homework, just use the comparison test |cos(1/x)| <= 1, so x cos(1/x) < x which -> 0
*August 17, 2014*

**programming**

in unix, there is usually a file named /usr /dict /words It may be named somewhat differently, or be located somewhere nearby, but you can probably find it. If not on unix, look for some such file name. As for rhyming, good luck. That is where the art of programming comes in. ...
*August 17, 2014*

**maths**

p'(x) = 4x^3 + 3ax^2 + 2bx + c since p'(0) = 0, c=0 and p'(x) = x(4x^2+3ax+2b) Since p' has no other roots, 9a^2-32b < 0 a^2 < 32b/9 p(-1) = -4+3a-2b+c p(1) = 4+3a+2b+c It appears that the answer is (c) Consider x^4+x^3+x^2 min is at (0,0) max at (1,3) ...
*August 17, 2014*

**Math**

(22-2w)(26-2w) = 396 w = 2 24*26-396 = 228 No, not enough brick 22*26 - (22-2w)(26-2w) = 160 w = 1.8 Not sure how #3 relates to #1 as with all such problems, divide the fencing evenly between the lengths and the widths. That means that a square 50/4 feet on a side will provide...
*August 17, 2014*

**science cbse school**

clearly the masses total 5+2.5 = 7.5 kg So, what's 10/7.5?
*August 17, 2014*

**Algebra**

It appears that the 0 was a typo for ), making the problem 5(14-2)^2/2 = 5*12^2/2 = 5*144/2 = 360
*August 16, 2014*

**Geometry**

The three lines intersect to form a triangle. Naturally, there is one circle inside the triangle, and three circles outside the triangle, all of which touch the three lines. The three lines intersect at (2,5),(5,-1),(-3,-5). If we call those vertices A,B,C, then the opposite ...
*August 16, 2014*

**Could you please check my answers.**

1) - 1.8 - 3.9 a- -2.1 b- 5.7 c- 2.1 d- -5.7* 2) -7 = 5 a- -2* b)12 c) -12 d) 2 3) -6.1 + 1.7 a-7.8* b- -4.4 c- -7.8 d- 4.4 4) A mountain climber ascends a mountain to it peak. The peak is 12,740 ft above sea level. The climber then descends 200 ft. to meet a fellow climber. ...
*August 15, 2014*

**Geometry**

for sides a<b<c c-b < a < c+b So, if 3L is the longest side 15-L < 3L < L+15 15 < 4L < 2L+15 L > 3.75 L < 7.5 So, the extreme is 7,15,21 for a perimeter of 43
*August 15, 2014*

**Trigonometry**

3 rides = 3 * 12.4 = 37.2 revolutions So, the angle moved is 2pi * 37.2 = ? radians The distance traveled is 2pi * 37.2 * 18.3 = ? meters
*August 15, 2014*

**Precalculus/Trig**

(cos+1)/sin^3 = csc/(1-cos) multiply by (1-cos) (1+cos)(1-cos)/sin^3 = csc = 1/sin (1-cos^2)/sin^2 = 1 sin^2/sin^2 = 1 1 = 1 (sin+cos)(tan+cot) = sec+csc sin*tan + cos*tan + sin*cot + cos*cot = sec+csc sin^2/cos + sin + cos + cos^2/sin = sec+csc (sin^2+cos)/cos + (sin^2+cos^2...
*August 15, 2014*

**math i need help 3 questions**

I'll do #1. How about you show some effort on the others? Just write the words in symbols. If the fraction is n/d, then we are told n/d = 3/4 (n+4)/(d-4) = 4/3 Work through all that, and you have n=12,d=16 check: 12+4 / 16-4 = 16/12 = 4/3 OK
*August 15, 2014*

**math**

set it up as a units conversion problem. b books = d dollars, so b bk/d dol = 1 d dol/b bk = 1 That is, books go at the rate of b/d books/dollar, or d/b $/bk Now, you want to convert d books to dollars. You can always multiply by 1, so do it to cancel the units you don't ...
*August 15, 2014*

**math**

Nope. (D) Did you draw a diagram? Do so, and label the points. You will have 3 equal sections: AB,BC,CD. AC is twice as long as CD.
*August 15, 2014*

**math**

If b lies on ac, then ab+bc = ac x+3 + 2x = 4x-5 x = 8
*August 15, 2014*

**compose**

I'm sure that there are those who would consider any of the choices to be the best. It's a purely subject opinion, based on one's own criteria. And what does that (or either of you other posts) have to do with homework?
*August 15, 2014*

**math**

nothing to solve. However, if you meant x^2-3x+4 = 0, the two complex values of x that make it true are 3/2 ± √7/2 i If you meant to type x^2-3x-4 = 0, then that factors to (x-4)(x+1) = 0 and it should be clear which values of x are solutions there.
*August 15, 2014*

**trigonometry**

If you mean 37°49', then clearly sin 37°49' = 1.5/x now just solve for x, the length of the plank. Oh, and review your basic trig functions.
*August 14, 2014*

**EEeeeeewwww**

eeewwww. You've ruined unicorns for me forever!
*August 14, 2014*

**Math - eh?**

no idea what all the carets represent.
*August 14, 2014*

**help me**

how about you list the six steps. Then apply each step. We'll be happy to check your solution. Wouldn't hurt to bone up on your English, as well...
*August 14, 2014*

**Programming**

Try something like this: main() { int x[1000],y[1000],i; for (i=0;i<1000;i++) {read x[i]} y = rev(x,1000); for (i=0;i<1000;i++) {printf("%d ",x[i]} } int *rev(*int,n) { int y[1000],i; for (i=0,n--;i<1000;i++,n--) {y[i] = x[n-i]; return y; }
*August 14, 2014*

**math corrections**

Since no coin duplicates the amounts of combining other coins, the number of items could be as many as 4C1 + 4C2 + 4C3 + 4C4 = 15 Note that the sum of the nth row of Pascal's triangle is 2^n, but we are missing 4C0=1, leaving only 15 combinations. This is also the number ...
*August 14, 2014*

**Algebra**

from eq #1, 6x = 5y-1 sub that into #2, and you get 5y-1 + 4y = 10 9y = 11 y = 11/9 Now you can get x
*August 14, 2014*

**Algebra**

12x+18y+8 <= 80 x+y <= 7 x > 0 y > 0
*August 14, 2014*

**maths**

the "rays" instead of "raised" doesn't help any. I read it as ((36/25)^(3/2)) ^ (5/3) due to the sly "whole" meaning "all that has come before". Now, since 36 = 6^2, 36^(3/2) = 6^3 25 = 5^2, 25^(3/2) = 5^3 Now, raise those to the 5/3...
*August 14, 2014*

**math**

rectangle: 2(x+2x) = 24 3x = 12 x = 4 So, the rectangle has area 2*4*8 = 64 Now, the square has side 8, so its perimeter is 32.
*August 14, 2014*

**math**

the other side, x, satisfies 4.2^2 + x^2 = (x+14)^2 Hmmm. You sure there's no typo?
*August 14, 2014*

**math**

a convex polygon with five equal sides. if you google that, you will see many images and descriptions.
*August 14, 2014*

**math**

since p = 2(x+y) = 8y, x+y = 4x x = 3y y:x = 1:3
*August 14, 2014*

**Math**

see the many related questions below
*August 14, 2014*

**Math**

OK. First, it's lookout, not lockout. The man is 25-1.7 = 23.3m up. If the building is at distance x from the tower, and has height h, we have 23.3/x = tan 70°20' (h-23.3)/x = tan 12°40' Now, you can eliminate x, and then solve for h: 23.3/tan70°20'...
*August 14, 2014*

**trigo**

As I interpret the data, it appears that the law of cosines will provide our answer. We want the supplement to θ, where 15^2 = 6^2+9^2 - 2(6)(9)cosθ cosθ = -1 Nope, that doesn't work. Maybe you can just describe the figure, giving labels to the points of ...
*August 14, 2014*

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