Tuesday
May 3, 2016

Posts by STEVE

Total # Posts: 40,096

Math
you have to add x on each side, or 2x to both dimensions. So the perimeter is 2(5+2x+ 10+2x) = 30+8x
April 1, 2016

math
7:35
April 1, 2016

Calculus
draw your triangle You have the opposite leg=12 and the hypotenuse=13 So, the adjacent leg is √(169-144) = 5 cot(x) = 5/12
April 1, 2016

Math
If you mean ln(23x)+1 = 5 ln(23x) = 4 23x = e^4 x = e^4/23 If you mean ln(23x+1) = 5 23x+1 = e^5 x = (e^5-1)/23 Get used to being specific online.
April 1, 2016

Math
If x at 12%, then .12x + .15(5000-x) = 700
April 1, 2016

Brief Calculus
f' = 12x^2 - 18x - 30 Now use your Algebra I skills. (A) the critical numbers are where f'=0 (B) f is increasing where f' > 0.
April 1, 2016

precalc
Using the usual formulas, sin42°+sin18° = 2 sin30° cos12° since sin30° = 1/2, that is just cos12° = sin78° cosine means sine of the complement.
April 1, 2016

Math
if the drawing is 1 x 1.25 inches, then clearly each inch represents 20 feet.
March 31, 2016

Math
multiply all the numbers by 7 so that the largest is 42. 14:21:35:42 that should help.
March 31, 2016

Mathematics
so, if you plug in 12 for t, how do you get 12/3 = 15? You apparently did 12+3=15 better review what the operators mean.
March 31, 2016

Mathematics
well, it's bogus. It's already a whole number of dollars. Rounding to the nearest dollar doesn't mean anything unless there are some cents. $2200.51 rounds up to $2201 $2200.23 rounds down to $2200 $2200 rounded to the nearest thousand is $2000
March 31, 2016

Math
Draw a diagram. If the base of the rectangle is the segment (a,0) to (b,0) then the upper vertices are (a,4a) and (b,6-5b). Since it is a rectangle, the height is the same, so 4a = 6-5b. That is, b = (6-4a)/5 Now, the area is (b-a)(4a) = ((6-4a)/5-a)(4a) = 12a/5 (2-3a) This is...
March 31, 2016

pr calc 11
The quadratic formula works with all quadratics!! h = -0.09x^2+x+1.2 h(x) = 0 when x = [-1±√(1^2-4(-.09)(1.2))]/(2(-.09) = (-1±√1.432)/-0.18 = -1.09 or 12.20 Now, how does that answer the question? It means that when the water shoots out, it will hit ...
March 31, 2016

pr calc 11
just solve h(x) = 0
March 31, 2016

algebra
Since time = distance/speed, d/24 + 1/6 = d/30
March 31, 2016

Math 142 (Pre-Cal) (Circles)
looks good to me.
March 31, 2016

math help pls pls pls
correct.
March 31, 2016

math help pls pls pls
Assuming you know what the standard form is (highest degree first), then can you determine the degree of each term? Just add exponents of all the variables. what if two terms have the same degree? I have checked a few discussions, and none mentions that wrinkle. Check your ...
March 31, 2016

algebra 1
$42
March 31, 2016

algebra
just sub in2x+2 for y x^2+3x-4 = 2x+2 x^2+x-6 = 0 (x+3)(x-2) = 0 ... or, without solving, you could just check each of the choices... duh
March 31, 2016

Math
If the sides in order of length are a,b,c then b = a+7 c = b+2 = a+9 a^2+b^2 = c^2 a^2+(a+7)^2 = (a+9)^2 a=8, b=15, c=17 I think you can take it from there, right?
March 31, 2016

Hi need help with math
what's all this shape stuff?
March 31, 2016

algebra
all those words! f(x) = |x| if -3 <= x < 1 4 if 1 <= x <= 8 Just plot each line, and mark off the sections you want. http://www.wolframalpha.com/input/?i=plot+[piecewise+[{{|x|,+-3%3C%3Dx%3C1},{4,+1%3C%3Dx%3C8}}]]
March 31, 2016

College Algebra/pre-calculus
since the value starts at $8000 and decreases by 7000 in 10 years ($700/year), the equation for the value is y = 8000 - 700x at x=6, y = 8000 - 4200 = 3800
March 31, 2016

math
a constant rate (slope) means a linear function. So, which of those is linear?
March 31, 2016

Math
of the 52 cards, how many are a heart or a 10?
March 31, 2016

math
P(pop) = 9/92 so, P(0 pop) = (83/92)^13 P(1 pop) = 13C1 (9/92)(83/92)^12 add them up
March 31, 2016

vectors
suppose we say that vectors u = force of 125 N pulls due west v = force of magnitude v pulls N 28.79 W r = resultant force is 212 N at angle b expressing those in x-y coordinates, u+v = r <-125,0> + <-v sin 28.79,v cos28.79> = <212 cosb, 212 sinb> <-125,0&...
March 31, 2016

Algebra 2
correct all the way. Good work.
March 31, 2016

Geometry
.015mi * 5280 ft/mi / .005hr * 1hr/60min * 1rev/2πft = 414.69 rev/min
March 31, 2016

Solid Mensuration
what is the cross-section?
March 31, 2016

Geometry
a = πrs, so 46πs = 736π s = 16
March 31, 2016

Math
1/42^42
March 31, 2016

Algebra
x + x/7 = 88
March 31, 2016

simple interest
since 12% is 2/3 as much interest, 3/2 as much should be invested there. Or, since the interest ratio is 2:3, the investment should be 3:2 So, 40% at 18% and 60% at 12% .12 * 7200 = .18 * 4800 = 864 or, in the usual algebraic way, .12x = .18(12000-x)
March 31, 2016

simple interest
.09x + .15(14000-x) = 1800 better check your work
March 31, 2016

simple interest
mine, too
March 31, 2016

simple interest
.10x + .12(8000-x) = 900
March 31, 2016

MATH
After you arrive at an answer, you need to do a sanity check. Your answer makes no sense. The problem says that the membership rose by 30% to 182. So how can you possibly accept the answer that last year it was 425? a proportion needs two ratios or fractions: 182/x = 1.30/1.00
March 31, 2016

math
1.25^2 = 1.5625 why do you say that 3.14 * 1.25^2 = 1.5625? (a) where does 1.11803 come from? (b) how can you say with a straight face that 10*1.11803 = 33.20? You have some serious problems here, either with calculation or typing.
March 30, 2016

geometry and trig
not sure what you're doing wrong, because you haven't said what you are trying to do. But if you want the side length, then if it is s, then you do have (s/2)/9 = sin(22.5) s = 18*.3826 = 6.888
March 30, 2016

Real Analysis (Math)
since the limit on the left is 0 and on the right it is 1, There is clearly no L such that limit(delta->0) |f(x)-epsilon| < 0 if |x-0| <= delta
March 30, 2016

Math
you might consider carrying the units along at each step. (d m)/(400 m/min) = d/400 min Makes sense, since distance/speed = time Using your equations, multiplying 6 min * 400m/min = 2400m makes sense, since the distance d is in meters.
March 30, 2016

precalc
(2^(3+h) - 2^3)/(8h) = (8*2^h -8)/(8h) = 8(2^h - 1)/(8h) = (2^h - 1)/h f(x) = 2^x g(x) = √(x-7) (g◦f)(5)/(f◦f)(3) = √(f(5)-7)/2^(f(3)) = √(2^5-7)/2^(2^3) = √(32-7)/2^8 = 5/256
March 30, 2016

Trigonometry
the gradient is the slope, is the tangent of the angle. So, tan(theta) = y/x = 0.700/-0.714 find theta. It will be in QII
March 30, 2016

Math
since time = distance/speed, d/400 + d/80 = 6
March 30, 2016

Math
base area = B face area = 2B total surface (two bases + 3 faces): 2B + 3(2B) = 80
March 30, 2016

Physical Science
The voltage across each resistor is the same: 120V then, for each resistor Ri, the current is Ii = 120/Ri amps
March 30, 2016

algebra
y^a * y^a + 2 y^(2a) + 2 Not sure where you want to go with that. or, assuming the usual carelessness with parentheses, y^a y^(a+2) = y^(2a+2) = (y^(a+1))^2 = (y^2)^(a+1)
March 30, 2016

Math
there are only two choices π*2^2*9 = 36π π(9/2)^2*2 = 81/2 π The radius will be half the rolled dimension.
March 30, 2016

ALGEBRA ONE
correct.
March 30, 2016

ALGEBRA ONE
the first and last numbers must be perfect squares. So, B is out. The middle number must be twice the product of the roots of the 1st and last, since (a+b)^2 = a^2+2ab+b^2 If we check 9x^2+9x+1, a=3 and b=1, but that would need 2*3*1 = 6x in the middle. So, (A) is out. Check ...
March 30, 2016

alg
No. (x+4)(x-4) = x^2-16 (x-4)(x-4) = x^2-8x+16
March 30, 2016

Math
AB = 5 AC = √85 BC = √40 Call the angle x. Then by the law of cosines, 40 = 25+85-2*5√85 cos(x)
March 30, 2016

Algebra 1-Factor by Grouping Help!
I'll admit that if the question is unclear, so will be the answer. Better check with your teacher.
March 30, 2016

Algebra 1-Factor by Grouping Help!
Well, there must be a typo somewhere, because if we say -7+49 = 42, then we have 3u^2-21u+42 and that does not factor.
March 30, 2016

Algebra 1-Factor by Grouping Help!
since you have 3u^2, look for multiples of 3: 3u^2-21u = 3u(u-7) Work on that idea. But why both the -7 and +49 constant terms? Looks like a typo to me.
March 30, 2016

ALGEBRA
HUH? I told you which one. See any minus signs anywhere?
March 30, 2016

ALGEBRA
since the 1st and last are perfect squares, look for (3x+7)^2 = 9x^2+42x+49
March 30, 2016

algebra
Since it is a perfect square, it's easy to check. (a-b)^2 = a^2-2ab+b^2 so you know that a=3 and b=1 (3x-1)^2 = 9x^2-6x+1
March 30, 2016

Math
If there were m monkeys, then the rest (24-m) were lions. m = 3(24-m) ...
March 30, 2016

Math
22.00(1+.06875)
March 30, 2016

Math
1:150 / 1:300 = 1:150 * 300:1 = 2 2x2 = 4
March 30, 2016

math
S = 80/2 (7+393)
March 30, 2016

algebra
-16 + m^2 - 6m m^2 - 6m - 16 so, what two factors of 16 differ by 6? (m-8)(m+2)
March 30, 2016

Math algebra
well, 36 = 2^2 * 3^2 Not sure what that has to do with x,y,z
March 30, 2016

Geometry
The diagonals bisect each other, and are perpendicular. So, drawing the diagonal of 14, you have two triangles with base 14 and altitude 1/2 of the other diagonal. So, if the other diagonal has length 2x, then 2( 1/2 * 14 * x) = 31 x = 31/14 and the other diagonal is 31/7 ft
March 30, 2016

College algebra
How many pounds of nuts selling for$6/lb and raisins selling for $3/ lb should a person combine to obtain150 lb of trail mix selling for $4/lb?
March 30, 2016

mathematics-calculus-derivatives
do you mean the 5th derivative? d5y/dx5? dy/d(5x) = 1/5 dy/dx If that makes any sense. start taking derivatives -- you will see a pattern.
March 30, 2016

maths
The question makes no sense. It will "look" 1.9m wide from any distance. There must be more to the question.
March 30, 2016

math
since time=distance/speed, 25/x + 1 = 30/x x = 5 some slow rider!
March 30, 2016

math
you got rid of the subtraction by adding. Get rid of the division by multiplying. m/5 * 5 = 29*5 m = 145
March 30, 2016

math
CD has slope 2/3 so, QC has slope -3/2 CD: y+6 = 2/3 (x+3) CQ (since it contains point C): y+6 = -3/2 (x+3) At x = -1, y+6 = -3/2 (-1+3) y+6 = -3 y = -9 Q is thus (-1,-9)
March 30, 2016

arithmetic progression
a(a+3d) = 70 (a+d)(a+2d) = 88 Since 88=8*11, I'd guess that T2=8 and T3 = 11 so, that makes T1=5 and T3=15 or, you can solve the equations using algebra.
March 30, 2016

Math
recall the formula: v = 1/3 pi r^2 h Now just plug in your numbers.
March 30, 2016

trignometry
well, recall that (tanx + cotx)^2 = tan^2x + 2tanx*cotx + cot^2x
March 30, 2016

math (algebra 1)
60(1+.10)^3 = 79.86, but that is how much will be in the account. As you note, only $19.86 of that is the interest, which answers the question asked.
March 30, 2016

pr calc 11
(x+2)^2-(x+2)-42 Note that (u-7)(u+6) = u^2-u-42 So, letting u=x+2, we have (x+2-7)(x+2+6) = 0 (x-5)(x+8) = 0 as above
March 30, 2016

Calculus
y = √(x+√(x+√(x+...))) y^2 = x+√(x+√(x+...))) y^2 = x+y 2yy' = 1+y' y' = 1/(2y-1) = 1/[2√(x+√(x+...)))-1]
March 29, 2016

Math
you are correct.
March 29, 2016

maths
theta, not thita. I'll just use x. You want sin x = 0.5623 Since sin is positive in QI and QII, and sin(34.2°) = 0.5623 the solutions are x = 34.2° and 180-34.2°
March 29, 2016

pre calc 12
well, just solve for t when -5t^2 + 12t + 2 = 12 But I suspect a typo, since the maximum height reached is 9.2m ??
March 29, 2016

Algebraic
x^2-6x - 12 (x^2-6x+9) - 12-9 (x-3)^2 - 21 so, setting (x-3)^2 - 21 = 0 (x-3)^2 = 21 x-3 = ±√21 x = 3±√21
March 29, 2016

algebra
such as ... ?
March 29, 2016

math
so, you have the numbers and the formula. What's the trouble?
March 29, 2016

Math
You are correct. The function should be h(t) = 25t - 5t^2 The -5t^2 term is due to the downward pull of gravity. The +25t indicates an initial upward velocity.
March 29, 2016

Cartesian Equation
see a good discussion of a similar problem here: http://math.stackexchange.com/questions/199475/find-an-equation-of-the-plane-passing-through-2-points-and-perpendicular-to-anot google is your friend.
March 29, 2016

math
you want to find $/g. So, start working with the units: 12.0gal/66lb * 3.50 $/gal * 1lb/454g = $0.0014/g or .14¢/g
March 29, 2016

math
j = 2s j = m-2 m = s+7 So start substituting till you get to j.
March 29, 2016

math
13+5M
March 29, 2016

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

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