Friday

April 29, 2016
Total # Posts: 40,006

**Math**

If x gallons of apple, then 2x + 3.50(10-x) = 26
*March 29, 2016*

**geometry**

C = 180-55-44 = 81 Since AB is side c, the law of sines tells us that AB/sinC = b/sinB Now just plug in your numbers.
*March 29, 2016*

**Geometry**

Check your formula for the area of a cone. A = πr^2 + πrs where s is the slant height: √(r^2+h^2) So now, just plug in your numbers.
*March 29, 2016*

**Math**

lots of resources online. Google is your friend.
*March 29, 2016*

**math**

78 / 9 x 3 + (6 - 9) 78 / 3 + (-3) 26 - 3 23 Note that I did (1/9 * 3) first, due to the fact that 78/9 is not an integer, but 78/3 is. (78/9)*3 = (78*3)/9 = 78*(3/9) = 78/3
*March 29, 2016*

**Check My Answer! :)**

If the height of each triangular face is 4, then the area including base is 36 + 4*6*4/2 = 84 without the base, it's 48 If it is 5, then the area is 36 + 4*6*5/2 = 96 without the base, it's 60 So, you can see that much important information has been omitted. The answer...
*March 29, 2016*

**Check My Answer! :)**

what is the difference between altitude and height? 144 = 36 + 4*27 I can't "square" that with the dimensions given, assuming the base is 6x6. So, what's the difference between the height and the altitude?
*March 29, 2016*

**Calc 2**

If you want an explicit function, then you are correct.
*March 29, 2016*

**Calc 2**

du/dt = (2t + sec^2(t))/(2u) 2u du = (2t + sec^2(t)) dt u^2 = t^2 + tan(t) + c 16 = 0+0+c u^2 = t^2 + tan(t) + 16
*March 29, 2016*

**Calc 2**

yes.
*March 29, 2016*

**Calc 2**

dy/dx = x/y y dy = x dx y^2 = x^2 + c 49 = 0 + c c = 49 y^2 - x^2 = 49
*March 29, 2016*

**Math**

LCM(44,56) = 7*8*11 So, there will be 14*44 by 11*56 = 616x616 mm, using 14*11 = 154 tiles
*March 29, 2016*

**Mathematics**

so, did you do it?
*March 29, 2016*

**Math**

S150 = 150/2 (2*15 + 149*2)
*March 29, 2016*

**physics**

If I understand conservation of energy correctly, if her weight is mg, then the loss of PE going from 2m to 1m is mg Joules. So, since that is converted to KE, we have mg = 1/2 mv^2 2g = v^2 v = √19.6 m/s
*March 29, 2016*

**Calculus**

You have to remember what the derivatives mean. To start with, your derivatives are incorrect: f = (2x+2)/(x-2) f' = -6/(x-2)^2 f" = 12/(x-2)^3 Fortunately, this small error does not affect their properties in any relevant way. Now, local max/min are where f'=0 ...
*March 29, 2016*

**Business Math**

If x is at 5%, the rest (98000-x) is at 10%. So, just add up the interest: .05x + .10(98000-x) = .08(98000)
*March 29, 2016*

**permutation**

8P5 = 8*7*6*5*4
*March 29, 2016*

**Math**

cos(x)
*March 29, 2016*

**mathematics**

that would be u•v×w = |3 -5 1| |0 2 -2| = 36 |3 1 1|
*March 29, 2016*

**Math**

well, just add up the numbers.
*March 29, 2016*

**math**

9:50 to 10:00 = 10 minutes 10:00 to 10:45 = 45 minutes so, just add it up for the cassettes, subtract to see how much total was spent. Since it was for 2 cassettes, divide by 2 to get each one's cost: (20.00-2.04)/2 = ?
*March 28, 2016*

**maths**

x^a * x^b = x^c so, x^b/x^c = 1/x^a similarly, y^c/y^a = y^b y/x = z/y (x^b/x^c)× (y^c/y^a)× (z^a/z^b) = 1/x^a * y^b * z^a/z^b = (y/z)^b * (z/x)^a = (x/y)^b * (y/x)^2a = (x/y)^(b-2a) Now, since b-a = c-b, 2b=a+c b-2a = b-a + b-c = 2b-(a+c) = 0 (x/y)^0 = 1
*March 28, 2016*

**Alam**

After t1 seconds, v = x*t1 s = x/2 t1^2 after t-t1 more seconds, s = (x*t1)(t-t1) - y/2 (t-t1)^2
*March 28, 2016*

**Calc 2**

What is the shaded area?
*March 28, 2016*

**Math**

Let O be the center of the circle. Let the chord be labeled QR. Draw a radius bisecting the chord at P. Draw radii OQ and OR. Now you have a right triangle OPQ with OP=6 and OQ (the hypotenuse) = 10. So, PQ = 8 and the chord QR = 16
*March 28, 2016*

**C++**

first step: try compiling the code. What errors do you get?
*March 28, 2016*

**C++**

#1 If x and y are numbers, then &x and &y are their addresses. So, False. #2 If x and y are pointers, then since they point to the same thing, the values pointed to are equal. So, True.
*March 28, 2016*

**Math**

Looks like 100 to me. No smaller number is a multiple of 4,10,25.
*March 28, 2016*

**maths**

40 / (2/3) = ?
*March 28, 2016*

**maths**

you seem to know the formula. What do you get? We'll check it for you.
*March 28, 2016*

**Math**

use google to search for math word problem on rates and ratios and you will get lots of examples and discussions.
*March 28, 2016*

**Physics**

You know that F = GMm/r^2 so, what happens to F if r is replaced by r/2? F' = GMm/(r/2)^2 = 4GMm/r^2 = 4F use the same technique when replacing the other quantities.
*March 28, 2016*

**physics steve or damon help!!!!**

You know the rock is falling for 3 seconds. Why? (the horizontal speed is constant) So, how far does it fall in 3 seconds? h = 1/2 at^2
*March 28, 2016*

**Algebra**

You specify no distance, so let's work with the per/km cost. For x trucks of A and y trucks of B, you want to minimize c=30x+40y subject to 20x+30y >= 3000 40x+30y >= 4000 Now crank out the vertices.
*March 28, 2016*

**math**

what, got no calculator? Post whatcha got, and we can check it.
*March 28, 2016*

**math**

55/1320 = tan x
*March 28, 2016*

**math**

h/35 = tan40
*March 28, 2016*

**math**

for m miles, you want 0 + 0.90m = 50 + 0.70m
*March 28, 2016*

**algebra 2**

How much of a house can they paint in a day? 1/4 + 1/3 = 7/12 So, at 7/12 house per day 105 / (7/12) = 180 days = 36 weeks
*March 28, 2016*

**Trigonemtry**

Draw a diagram. Review your basic trig functions. The shadow's length x is found by x/100 = cot 25°
*March 28, 2016*

**algebra**

If the width is w, and the length is x, then w*x*(3/4) = 48 wx = 64 The only integer factors of 64 greater than 2 are 4,8,16,32 So, the base of the prism must be 4x16 Of course, if integer values are not required, any number greater than 2 will work as the width, as long as ...
*March 28, 2016*

**Math**

Don't you think you need some data on the expected lifetime of the units?
*March 28, 2016*

**math**

the amount is x-y as a fraction of the salary, (x-y)/x
*March 28, 2016*

**Geometry**

Only for the coordinate planes. Slanted planes produce other results.
*March 28, 2016*

**math**

well, how many of the cards are diamonds or 6's?
*March 28, 2016*

**math**

8 of the 52 cards are jacks or twos. So, ...
*March 28, 2016*

**math**

clearly (i) is binary op, since rationals are closed under multiplication and addition. (ii) is not, since x.y might produce a value not in [0,pi]. For any value xy in[pi/2,pi], cos(xy) < 0, so is not in the domain. I think you can answer the other questions: is a.(b+c) = a...
*March 28, 2016*

**math**

For a discussion with examples, take a look here: http://www.solitaryroad.com/c138.html
*March 28, 2016*

**Maths**

clearly n=0 is the only solution.
*March 28, 2016*

**Maths**

if you are using base 10, then log x^3 = 1/2 3 logx = 1/2 logx = 1/6 x = 10^(1/6)
*March 28, 2016*

**Math**

√850 = 29.15 so, she can tile a 29x29 countertop subtract 29x29 from 850 to get the remainder.
*March 28, 2016*

**physics**

you know that with initial velocity v and acceleration a, s(t) = vt + a/2 t^2 so, 5v + 25a/2 = 80 10v + 50a = 80+180 v=6 and a = 4 check: s(t) = 6t + 2t^2 s(5) = 6*5 + 2*25 = 30+50 = 80 s(10) = 6*10 + 2*100 = 60+200 = 260 = 80+180
*March 28, 2016*

**Calculus**

you don't have to change back to x. Just use horizontal strips instead of vertical ones. Using symmetry, your area is just twice the area in [0,π/4] and since it's also symmetric horizontally, it's twice the area between the y-axis and the curve. a = 4∫[...
*March 28, 2016*

**Calculus**

well, is it continuous? Clearly yes, so the IMT is satiisfied.
*March 28, 2016*

**Calculus Urgent**

It's not surprising that the two curves are so close. As you learn about functions, you will come across the Taylor Series. Any function can be approximated over a limited domain by a polynomial. This is handy, because polynomials are well behaved. Anyway, you will find ...
*March 27, 2016*

**physics**

google is your friend.
*March 27, 2016*

**math essentials**

well, whatever the factor, if it is x, then the area is reduced by a factor of x^2. xL * xW = x^2(LW)
*March 27, 2016*

**math**

?? Don't forget your basic Algebra I skills now that you're in trig. y = 2arcsin(x-5) y/2 = arcsin(x-5) sin(y/2) = x-5 x = sin(y/2)+5
*March 27, 2016*

**Algebra**

well, how far did she go altogether on the first 3 days?
*March 27, 2016*

**Math troubles**

Hmmm. I got .08789 + .01465 + .00097 = .10352 Looks like you have some problems. Make sure you are calculating your binomial coefficients correctly.
*March 27, 2016*

**Math troubles**

First off, no probability can be more than 1, so you calculations are off. P(x=3) = 5C3 .25^3 .75^2 P(x=4) = 5C4 .25^4 .75^1 P(x=5) = 5C5 .25^5 .75^0 Having gotten those, yes, you add them up.
*March 27, 2016*

**math**

google is your friend.
*March 27, 2016*

**maths**

well, shucks -- what are cos(pi/3) and cos(pi/4)?
*March 27, 2016*

**math @Reiny**

The problem as stated above does not mention draining. However, your answer is one of the choices, so I guess his posting today was garbled.
*March 27, 2016*

**math**

None of those. the 4 gal of 25% antifreeze contains 3 gal water 1 gal antifreeze So, you need 2 more gal of antifreeze to make the result 50% algebraically, .25*4 + 1.00 x = .50(4+x)
*March 27, 2016*

**math**

600 * .30 + 300 * .60 = (300+600)x
*March 27, 2016*

**math**

20% of 36, of course
*March 27, 2016*

**Math**

Review your basic trig functions: the vertical height is y/120 = tan10° the distance walked is z/120 = sec10°
*March 27, 2016*

**computer**

I'm holding my flowchart up to the screen. Take a look. the algorithm is for n = 2 to 20 step 2 print n next n or, if you don't like for loops, i=1 n=2 NEXTI: print n n = n+2 i = i+1 if i <= 10 go to NEXTI stop
*March 27, 2016*

**calculus2 - eh?**

you want to try that again in complete sentences? The fragment when the casting temperature 1200 o C is bogus If this is a linear heat increase, no calculus is needed. If not, what model are you using?
*March 27, 2016*

**Progression**

we know that since b-a = c-b, x^c/x^b = x^b/x^a and the same for y and z. Try starting with that.
*March 27, 2016*

**science**

recall that the height h is h(t) = (500 sin30°)t - 5t^2 Now just find the vertex of that parabola.
*March 27, 2016*

**math**

the nature is easily found from the discriminant, B^2-4AC.
*March 27, 2016*

**calculus**

you know that |t-1| has a minimum at t=1, so 1-|t-1| will have a max there. Now just find the values at -9 and 6 and select the max and min
*March 27, 2016*

**calculus**

draw a diagram. Here is where implicit differentiation comes in handy. at the moment in question, the boat's distance x from the dock is 8 ft. The length of rope z is found by z^2 = x^2+8^2 so x^2 = z^2-64 x = √(z^2-64) Now start taking derivatives. The velocity and ...
*March 27, 2016*

**calculas**

just use the chain rule to get 18x + 128y y' = 0 Now just solve for y' and that's implicit, not explicit.
*March 27, 2016*

**math**

64*13 + 28
*March 27, 2016*

**maths**

so, did you draw the graph? Font problems in my browser caused your function to be garbled. Try typing it in, rather than copy/paste.
*March 26, 2016*

**Math**

well, it's the same as the probability of NOT choosing a green ball.
*March 26, 2016*

**Pre Calculus**

well, since profit is revenue less cost, P(x) = R(x)-C(x) you just need to solve for x in 0.002x^2 + 38x - 150000 >= 1650000
*March 26, 2016*

**math**

Your Algebra I is missing 3cos(x+4) = 1 cos(x+4) = 1/3 x+4 = arccos(1/3) x = arccos(1/3) - 4 = 1.231 also, 2π-1.231 = 5.052 sin^2(t) = 1/2 sint = ±1/√2 since sin π/4 = 1/√2 t = all odd multiples of π/4
*March 26, 2016*

**contempory math**

not enough to go on. All we have is A, 4G's, A, 5G's no telling how many G's we are expecting between the A's. 4,5 ... is not much info.
*March 26, 2016*

**math**

the diagonal has length √(8^2+8^2) = 8√2 So, the sides have length 8. The total area is thus 6*8^2
*March 26, 2016*

**mathematics**

Let x be Jane's age now y be John's age now They have said x+y = 25 (x-8) = 2(y-8) So, just solve for x and y.
*March 26, 2016*

**TRIGONOMETRY**

Or, more directly, tan = 1/cot = 1/√(cot^2) = 1/√(csc^2-1)
*March 26, 2016*

**Math**

product means multiply: x(x+2) = 80 Note that 8*10 = 80
*March 26, 2016*

**calculas**

if it's a max at t=0, it is a cosine curve. So, y(t) = (2.7/2) cos((2π/18) t) the velocity is y', so v(t) = -(1.35)(π/9) sin(π/9 t)
*March 26, 2016*

**calculas**

first, find the slope of the tangent line anywhere: y' = -3sin(3x) so, at x=π/4, y = -3sin(3π/4) = -3/√2 Now you have a point and a slope, so the line is y + 1/√2 = -3/√2 (x - π/4)
*March 26, 2016*

**Math**

66/36 = 18/x 66x = 18*36 x = 18*36/66
*March 26, 2016*

**PRECALC**

f(3+h) = 2^(3+h) = 8*2^h f(3) = 2^3 = 8 ... (g◦f)(5) / (f◦f)(3) = √(f(5)-7) / 2^f(3) = √(32-7) / 2^8 = 5/64
*March 26, 2016*

**calc 2**

g(x) = (x + 5/2)^2 - 25/4 p = -25/4 there are Euler's method calculators online.
*March 26, 2016*

**Algebra 1**

What grade represents a C? Let's say it's a 75. Then just consider the total points he needs to have a 75 average: 68 + p >= 2*75 If a C is some other number, then just make the adjustment and solve for p, the number of points he needs.
*March 25, 2016*

**Probability**

well, of the 52 cards, how may are a 3 or a K?
*March 25, 2016*

**Math**

42.5 <= 90-19x <= 52 -47.5 <= -19x <= -38 2.5 >= x >= 2
*March 25, 2016*

**Probability**

well, of the 52 cards, how many are a heart or a king?
*March 25, 2016*

**mathematics-probability**

well, the probability of getting a 6 on just the 1st roll is (1/6)^1 * (5/6)^3 Since you are allowed a 6 on any of the rolls, what do you think?
*March 25, 2016*

**Math**

2*8*6 + 2*3*6 + 2*3*8 = 180 in^2 How much she needs to buy depends on the width of the roll and how much overlap she uses during the wrapping.
*March 25, 2016*

**Math**

well, such a reflection takes (x,y) -> (-x,y) Now just plug in your numbers.
*March 25, 2016*

**Math**

you have a square of side 18 and 4 triangles with base 18 and height 12. So, since you know how to find the area of squares and triangles, just add 'em up.
*March 25, 2016*