Friday
February 24, 2017

Posts by STEVE

Total # Posts: 48,746

maths
From your sum-to-product formulas, sinA-sinB = 2 cos(A+B)/2 sin(A-B)/2 Using your values, that would be 2 cosx sin2y without knowing more about the relation between x and y, that's as far as we can go. If you supply the missing info, I'm sure you can finish it off.
February 7, 2017

math
k = m-4 k+3 = 2/3 (m+3) Now just solve for k and m.
February 7, 2017

Math
"10 to the power of 2" or 10^2 40 + x = 10^2 40+x = 100 . . .
February 7, 2017

Math
clearly the missing angle is 52° Find two corresponding sides with a known ratio, and use that ratio to find the missing values.
February 7, 2017

science
* ?
February 7, 2017

science
static electricity
February 7, 2017

math
If their ages are a < b < c then c = b+8 a = c-12 a+b+c = 88 ...
February 7, 2017

mensuration
6^2+8^2 = 10^2
February 7, 2017

Question on Integration
let x = 2sinh? x^2+4 = 4sinh^2?+4 = 4cosh^2? dx = 2cosh? d? Now the integral becomes ?x^3 / (x^2 + 4)^2 dx ?8sinh^3?/16cosh^4? 2cosh? d? ?tanh^3? d? see what you can do with that. using direct substitution, let u = x^2+4 du = 2x dx ?x^3 / (x^2 + 4)^2 dx (1/2)?x^2 / (x^2 + 4)^2...
February 7, 2017

Algebra
7d+2b = 11 2d+7b = 16 5d + 2(d+b) = 11 5b + 2(d+b) = 16 add the equations and you get 5(d+b) + 4(d+b) = 27 9(d+b) = 27 d+b = 3 similarly, b-d = 1 b=2 d=1 dog costs $1 burger costs $2
February 6, 2017

Math
Remember that a proportional relationship between x and y means that y = kx. There can be no extra constants floating around. A is a proportional relationship between y and x^2 Only C is a p.r between y and x. For #2, same thing applies.
February 6, 2017

Algebra2
Looks good to me
February 6, 2017

Algebra2
What is the product in simplest form? State any restrictions on the variable. 4a^5/7b^4 times 2b^2/2a^4 My answer is 4a/7b^2 except a=0 and b=0
February 6, 2017

Math
well, sinØ = 3/4 cosØ = ?5/4
February 6, 2017

Math
tan(-a) = -tan(a), so tan(a) = 5 so, cot(a) = 1/5
February 6, 2017

Algebra2
Thank you very much
February 6, 2017

Algebra2
Simplify the rational expression. State any restrictions on the variable. (n^4-11n^2+30)/(n ^4 -7n^2+10) My answer is n^2-6/n^2-2 except +-sqrt5 and +-sqrt2
February 6, 2017

math
sorry, an extra point is awarded by scoring an "extra point". A field goal is worth 3 points. At any rate, if they get the extra point after each touchdown, then their score for x touchdowns is y = 6x + 1x = 7x Saying the total score for "x" amount of ...
February 6, 2017

physics
(6000kg*9.8N/kg)/(4*.10m^2) = 147000N/m^2 = 147KPa
February 6, 2017

physics
what volume of water has a mass of 400kg? Divide that by 24m^2 to get the depth of the displaced water.
February 6, 2017

physics
2700 kg * 1m^3/1.25kg = 2160 m^3
February 6, 2017

Accelerated 1
# coins = c points = p point for star = 3p p = 10c
February 6, 2017

Math
If you mean y = 9x1/2 it is not even exponential. An exponential function has x in the exponent, such as y = 9 * (1/2)^x which would be decay, because powers of fractions get progressively smaller. If you don't know how to even make a chart, you are in trouble. For a chart...
February 6, 2017

Math
since time = distance/speed, 7.2*10^2km / 1.2*10^3km/hr = 0.6hr Now convert to minutes.
February 6, 2017

astronomy
mirrors, lenses
February 6, 2017

Algebra 2 help
Oh, please. In the first, place, you'd better go out and get a calculator. Or use your phone's calculator. Or, there are lots of calculators online. google, etc. wolframalpha.com allows you to give a formula and a value, such as http://www.wolframalpha.com/input/?i=4x...
February 6, 2017

math help quick please
stop guessing. Next step: 5x+2x-14 = 7 ... B works for the 1st equation, but not the second.
February 6, 2017

math help quick please
so, substitute y=x-7 into 5x+2y = 7 5x+2(x-7) = 7 ...
February 6, 2017

Math
see related questions below.
February 6, 2017

Algebra
x^3 + 5x^2 - 4x - 2 = (x-1)(x^2+6x+2) The discriminant of the quadratic is positive, so it has two real roots.
February 6, 2017

math
(3/8) / (3/4) = 3/8 * 4/3 = 1/2 Naturally. Since 1/8 is half as big as 1/4, so are three of them half as big as three fourths.
February 6, 2017

Maths
I think you meant 4;7;10;13 where An = 1+3n So, just solve for n where 1+3n > 150
February 6, 2017

Algebra
using the sum of two cubes, (x + 3)^3 + 10 = (x+3+?10)((x+3)^2 - (x+3)?10 + ?100) = x^2 + (6-?10)x + (?100-3?10+9) One root is clearly x = -(3+?10). You can see that the discriminant of the quadratic is negative, so there are no other real roots. Or, consider the graph. It is ...
February 6, 2017

Trig
since sin(x) = cos(?/2-x) arccos(t) + arcsin)t) = ?/2 In general, draw the triangle. In this case, take cosine of both sides. cos(arccos(t)) = t In your triangle, the adjacent side will be t, and the hypotenuse will be 1. The other leg is thus ?(1-t^2). So, sin(arccos(t)) = ?(...
February 6, 2017

MATH
The odds are 7:4 beat 4:7 lose, so 4/11 probability
February 6, 2017

Calculus
This is a trick question, in a way. You can go through the math of height and speed, using an unknown acceleration (you will find that this fails to have a solution when g=9.8 is used). Or, you can just note that since momentum is conserved, the speed at launch is exactly the ...
February 6, 2017

Math
the unknown sides are equal, say x. So, 54+x+30+x = 134 If you draw your trapezium and mark off the interior 30x30 square, you will find a right triangle at each end, with base 12 and hypotenuse x. So, the height of the trapezium is ?(x^2-144) making the area A = (30+54)/2 ?(x...
February 6, 2017

algebra 2
you need to get your typing straight × is the symbol for multiplication x is a variable name 9 (9 - 8x) = 2x + 3 81 - 72x = 2x + 3 78 = 74x x = 78/74 = 39/37 Note that you cannot subtract the 2x inside the parentheses. You have to expand the left side first. Try it with ...
February 6, 2017

algebra 2
[-4b -8] + [-1b -b^2] + 2b^3 plug in b=2 (-4(-2) - 8) + (-1(-2) - (-2)^2) + 2*(-2)^3 (8-8) + (2-4) + 2(-8) 0 - 2 - 16 -18
February 6, 2017

Math
400 mL of 1/2 strength juice contains 200 mL of juice Adding 100 mL of juice makes 500 mL containing 300 mL juice, or 60% juice.
February 6, 2017

math
Change the fractions to have the same denominator: 1/3 , 5/6 , 4/3 = 2/6, 5/6, 8/6 The numerators are 2,5,8 Clearly, 3/6 = 1/2 is added each time.
February 6, 2017

Maths
density of A: 1.2kg/(20*10*5)cm^3 = 1.2/1000 = 0.0012 kg/cm^3 = 1.2 g/cm^3 Block B is 6cm on a side, with a density of 1.2*1.4 = 1.68 g/cm^3 So, its mass is 1.68 g/cm^3 * 216cm^3 = 362.88 g = 0.36 kg
February 6, 2017

math
The amount of work is 8hr/day * 13men * 15day = 1560 man-hr So, you want x so that 10*26*x = 1560 x = 6 days
February 6, 2017

Algebra (plz)
(a+b)^2 = a^2 + 2ab + b^2 You need the first and last terms to be perfect squares, and the middle term to be twice their product. 4m^2-4mp+p^2 = (2m-p)^2 16s^2+56s+49 = (4s+7)^2 16c^2+72cd+81d^2 = (4c+9d)^2
February 6, 2017

las st
The vertical and horizontal distance components of the flare are y = 2400 + 120t - 4.9t^2 x = 207.84t The flare hits the ground when t=37.54 The tangent of the angle of direction at time t=37.54 is dy/dx = (120-9.8*37.54)/207.84 = -1.193 So, ? = -50° I am assuming that the...
February 6, 2017

Math
Hmmm. If m is the number of correct answers, then s = 5m-3(10-m) = 8m-30
February 5, 2017

math
I expect some information about g will help ...
February 5, 2017

Intermediate Algebra
same problem: If there are x liters of 25%, then the rest (50-x) is 60%. So, .25x + .60(50-x) = .40 * 50
February 5, 2017

Algebra
48/5
February 5, 2017

Math
it gains 1 meter each day. After 9 days it has climbed 9 meters On the 10th day it climbs 3 meters and is out.
February 5, 2017

Math
so, is -18 the max or the min? There is a double root at x=1, where it just touches the x-axis. It crosses the x-axis at x = -4 Since this is a cubic polynomial, with negative leading coefficient, it drops down from the left. So, it is decreasing on (-?,-4) and beyond to the ...
February 5, 2017

Algebra
the math looks good so far. Note that 99+77 is only half the perimeter.
February 5, 2017

Geometry
looks good so far.
February 5, 2017

Math
Check here: http://www.wolframalpha.com/input/?i=1%2F2+(+x%5E2-2x%2B15) Use what you know about quadratics to figure out what it shows. You can play around with other functions and see how things work...
February 5, 2017

pre calc
Too bad you didn't see fit to show your work... f(x) = 1/3 ?(1-2x) g(x) = (x-2)/x (g?g)(x) = g(g(x)) = (g-2)/g = ((x-2)/x - 2)/((x-2)/x) = 1 - 2x/(x-2) (g?f)(x) = (f-2)/f = (1/3 ?(1-2x) - 2)/(1/3 ?(1-2x)) = 1 - 6/?(1-2x) (g?g)(3) = 1 - 6/1 = -5 (g?f)(-24) = 1 - 6/7 = 1/7 (...
February 5, 2017

Algebra
Write an equation in point-slope form to represent each situation. Assume a linear relationship between the given quantities. A temperature of 50 degrees Fahrenheit corresponds to 10 degrees Celcius. A temperature of 77degrees Fahrenheit corresponds to 25 degrees Celsius. ...
February 5, 2017

Algebra
Thank you so much I found my mistake l added 10 to 2010
February 5, 2017

Algebra
Write an equation in slope-intercept form fo each situation. Assume a linear relationship between x and y. In 2007 Tamara bank account balance was $500. In 2010, it was $1,400. Assuming she saves the same amount each year, in what year will her balance be 3,500?
February 5, 2017

9th grade alebra
whole and natural exclude negative values, so C is the choice
February 5, 2017

Algebra
Thank you
February 5, 2017

Algebra
For each linear relationship identify the independent and dependent variables. Then calculate the rate of change / slope for each situation. Christopher has saved $65 after 3 weeks and $98 after 6 weeks.
February 5, 2017

Maths
you can construct a 60° angle, I'm sure. (make an equilateral triangle) Bisect that twice and you have a 15° angle Construct a right angle and subtract the 15° angle from that. Now you have your 75° angle, so just draw that angle with the sides as given ...
February 5, 2017

addmaths
well, no real roots means that the discriminant is negative. So you need (4m)^2-4(1)(2m+1) < 0 16m^2-8m-4 < 0 4m^2-2m-1 < 0 The roots of that quadratic are (1±?5)/4 So, the discriminant is negative when (1-?5)/4 < m < (1+?5)/4
February 5, 2017

Math
the sector will be a 1/4 circle of radius 24...
February 5, 2017

Algebra2
thank you
February 4, 2017

Algebra2
The amount of oil used by a ship traveling at a uniform speed varies jointly with the distance and the square of the speed. The ship uses 30 barrels of oil in traveling 85 miles at 42 mi/h. How many barrels of oil are used when the ship travels 26 miles at 54 mi/h? Round your ...
February 4, 2017

Math
36x^4 - 3x^3 - 18x^2 3x^2 (12x^2-x-6) 3x^2 (4x-3)(3x+2) 9x^2 + 3xy - 2y^2 (9x+)(x-) won't work; the 9 is too big 3*2 - 3*1 = 3, so (3x+2)(3x-1)
February 4, 2017

natural science
mass = density * volume, so since the two masses must be equal, the volume v we want is found by 8.96v = 11.4*1.15
February 4, 2017

Algebra
well, just plug and chug. .5 = 1/2 .5^2 = 1/2^2 = 1/4 .5^3 = 1/2^3 = 1/8 p^2q^2+pq–q^3–p^3 (1/4)(1/4)+(1/2)(-1/2) - (-1/8) - 1/8 1/16 - 1/4 + 1/8 - 1/8 -3/16
February 4, 2017

algebra
In thousands, let t be the number of years since 2009, since that is the year we have our first appraisal. V(t) = 475+(468-475)/(2014-2009) t = 475 - 1.4t But we want t to be years since 2005. That means we have to add back 4 more years of loss: 4*1/4=5.6 V(t) = 480.6 - 1.4t ...
February 4, 2017

Algebra
85(z-66) = z+10 why do you use all those words, when the math is so much clearer?
February 4, 2017

Algebra
The numbers are x and x+2 x + x+2 = -126 ...
February 4, 2017

algebra
as written, it is not an exponential function. Try using ^ for exponents and * for multiplication, as in 4 * 2^x
February 4, 2017

math
1.1 * 0.8 = 0.88 now you can get the change.
February 4, 2017

Math
|x+1| = |x-(-1)| That is the distance from x to -1 So, on the number line, mark the two points which lie 3 units away from -1: -4 and +2 Shade the area between those two points, where the distance from -1 is less than 3.
February 4, 2017

Math
Of course there is, though its form will depend on how the trapezoid is described. For simplicity, let's say that the bottom base goes from (0,0) to (a,0) and that the top base goes from (b,h) to (c,h). (Usually, this will mean that 0<=b<=c<=a) The area of the ...
February 4, 2017

Calculus
Just use the normal product and chain rules, with the chain rule: f=uv, f' = u'v+uv' f=u/v, f' = (u'v-uv')/v^2 Just take it a step at a time; you know how to get the derivatives of the various function involved. If you get stuck, come back with your ...
February 3, 2017

Calculus
just use the chain rule (a) h' = f'g + fg' = (12)(-3)+(-7)(-9) = 27 (b) h' = (f'g-fg')/g^2 = ((12)(-3)-(-7)(-9))/(-3)^2 = -11 (c) h' = (g'(1+f^2))-g(2ff'))/(1+f^2)^2 = ((-9)(1+(-7)^2))-(-3)(2(-7)(12))/(1+(-7)^2)^2 = -281376/625
February 3, 2017

Algebra2
thank you
February 3, 2017

Algebra2
Solve the equation 3^5sqrt(x+2)^3+3=27 My answer is 30
February 3, 2017

Math
well, she bought m pens, and each cost 6.70 So, the total cost for the pens is 6.70m same for the pencils, but there are m-4 of them.
February 3, 2017

math
correct I hope x is small, to be realistic...
February 3, 2017

math
2/13 + 1/3 = 6/39 + 13/39 = 19/39 so, 19/39 - 1/3 = 2/13
February 3, 2017

Math help PLEASE!!!!
sorry - can't see files on your computer.
February 3, 2017

Geometry
Divide it up into rectangles and triangles, which are easy to figure.
February 3, 2017

algebra
If the number is abc, then you are told a+b+c = 20 b = (a+c)/2 100c+10b+a = 100a+10b+c + woo Now just solve for a,b,c
February 3, 2017

math
review the 2nd Fundamental Theorem of Calculus. If ?ln(2t+1) dt = f(t), then G(x) = f(x) - f(1) So, naturally, G'(x) = ln(2x+1) the 2nd integral is just
February 3, 2017

calculus
the square has base 2y=2?x and height 2y=2?x and thickness dx So, v = ?[0,9] (2?x)(2?x) dx = ?[0,9] 4x dx ...
February 3, 2017

physic
well, the density of the mass is m/v So, how much of that is buoyed up by the liquid? Then the tension is the difference, times g.
February 3, 2017

chem
1 mole of a suitable substance.
February 3, 2017

math
a+16d = 3a-6 a = 8d+3 So, pick d and you have a: d=1, a=11 11,12,13,...,27 27 = 3*11-6 d=0, a=3 3,3,3,...,3 3 = 3*3-6 As you can see, any value of d will work.
February 3, 2017

Maths
see related questions below
February 3, 2017

math
sinB/b = sinA/a I suspect a typo
February 3, 2017

maths
just check all the pairs where one is a multiple of 7 and the other is not.
February 3, 2017

maths
sorry. 210 = 5*7 * 2*3
February 3, 2017

maths
210 = 5*7*3 ...
February 3, 2017

Math
h/w = 4/3 (h+4)/(w+4) = 9/7 h=32, w=24 (h-m)/(w-m) = 5/3 (32-m)/(24-m) = 5/3 m=12 They were married 12 years ago, when the ratio of their ages was 20/12 = 5/3 She was a child bride!
February 3, 2017

Math
That would be 55C26 (-3x)^29 (4y)^26 I'll let you do the arithmetic. Expect some large numbers!
February 3, 2017

Math
p(k) = 2k+5 k(p) = 3p+b 2k(x)+5 = 3p(x)+b b = 2k(x)-3p(x)+5 Unless you have some further information on the functions p and k, that's as far as we can go.
February 3, 2017

4th grade math
Harriet ate 1/4, leaving 3/4 uneaten. Nisha ate 1/2 of the 3/4, or 3/8, leaving 3/8 uneaten. 6 pieces was 3/8, so the whole bar was 6 divided by 3/8, or 6 * 8/3 = 48/3 = 16 pieces. Check Harriet ate 1/4, or 4 pieces, leaving 12. Nisha ate 1/2 of those, leaving 6. Works for me...
February 2, 2017

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