Saturday

May 30, 2015

May 30, 2015

Total # Posts: 1,856

**Algebra**

Represent the unknown: Let x = original number of students Let x+6 = new number of students (after six students decided to join) It was said that the original contribution of each was reduced by $4.80 after six people joined. Thus, (224 / x) - 4.80 = 224 / (x+6) solving, [(224...
*March 20, 2015*

**Math**

The cost of a carton according to problem = c Total number of plates = bn Thus the cost per plate is, c / bn hope this helps` `u`
*March 20, 2015*

**Arithmetic Reasoning**

8 games won /24 games total = 1/3 1/3 in percentage is 33.3%
*March 20, 2015*

**pre-calculus**

P(x) = 2x^4 - 3x^3 + 3x^2 + 5x - 3 To use rational root theorem, we get all the factors of constant divided by the factors of the leading coefficient (or the term with variable of highest degree). In this case, the constant is -3, and the leading coefficient is 2. Thus, +/- 1,...
*March 20, 2015*

**math**

Let x = height of building B Let x - 180 = height of building A since their total height is 1480, x + x - 180 = 1480 Solving, 2x = 1480 + 180 2x = 1660 x = 830 ft (height of bldg B) x-180 = 650 ft (height of bldg A) hope this helps~ `u`
*March 20, 2015*

**math 5th grade**

Target: 3 meters or 300 cm First day: 0 + 40 - 2 = 38 Second day: 38 + 40 - 4 = 74 Third day: 74 + 40 - 6 = 108 Fourth day: 108 + 40 - 8 = 140 Fifth day: 140 + 40 - 10 = 170 Sixth day: 170 + 40 - 12 = 198 Seventh day: 198 + 40 - 14 = 224 Eighth day: 224 + 40 - 16 = 248 Ninth ...
*March 20, 2015*

**math**

This is hard to solve if you don't draw it. So I hope you'll draw the figure, and I'll provide the steps here. Anyway, first, I'll rename some angles. Let angle AXB = n Let angle ABX = m Let angle ABC = B Let angle ACB = C It was said in the problem that angles...
*March 19, 2015*

**algebra**

3j^3 - 5ij^2 + 210j First, we factor out the most obvious factor (which is j, since all terms contain the variable j): j (3j^2 - 51j + 210) We can also see here that the terms inside the parenthesis have a common factor of 3, thus, 3j (j^2 - 17j + 70) To factor the quadratic ...
*March 19, 2015*

**math**

Limit of sin(x)/(tan(x)*sec(x)+tan(x)*sin(x)) as x approaches 0 simplify first the expression: sin(x)/(tan(x)*sec(x)+tan(x)*sin(x)) Note that tan(x) = sin(x)/cos(x) and sec(x) = 1/cos(x). Thus, sin(x) / (sin(x)/cos(x) * 1/cos(x) + sin(x)/cos(x) * sin(x)) sin(x) / (sin(x)/cos^2...
*March 18, 2015*

**chemistry**

BaCl2 (aq) + H2SO4 (aq) ---> BaSO4 (s) + 2HCl (g) BaSO4 (s) is the white precipitate in this reaction.
*March 18, 2015*

**Chemistry**

I think it's C, but I'm not really sure. Water is a polar molecule and table salt is ionic. Water and salt are both very polar. When placed in water, NaCl is surrounded first by water molecules and then NaCl dissociates to Na+ and Cl-. They are then attracted to the ...
*March 18, 2015*

**math.**

Yes that's right. `u`
*March 17, 2015*

**chemistry**

A and C are both endothermic, since energy is required to break bonds between solute-solute molecules and solvent-solvent molecules. The step that releases energy is when the solute and solvent are mixed (letter D).
*March 17, 2015*

**Chemistry**

Viscosity is simply the resistance to flow. If there is larger viscosity, then it has greater intermolecular force. thus, olive oil has greater intermolecular force than benzene. hope this helps~ `u`
*March 17, 2015*

**math**

To solve for y, first, we must isolate the term with y to one side of the equation. We can see that on the left side of the equation, the term with y is 3y, but the left side also has -6 in it. Thus we transfer it on the right, but its sign becomes the opposite (positive in ...
*March 17, 2015*

**Math**

Recall that speed is distance traveled over time: v = d/t Represent the speeds with variables: Let x = speed of Plane A Since it was said the speed of Plane B is 300 km/h faster than Plane A, Let x + 300 = speed of Plane B When they catch up, that means that their distance ...
*March 17, 2015*

**math**

Yes, that's right. `u`
*March 17, 2015*

**chemistry**

For a general reaction, aA + bB ---> cC the equilibrium constant, Kc, is given by Kc = [products] / [reactants] = (C)^c / ( (A)^a * (B)^b ) The reaction given is: 2 NH3 ---> N2 + 3 H2 Thus, Kc = (N2) * (H2)^3 / (NH3)^2 Plug in the concentration values given, and solve ...
*March 17, 2015*

**Chemistry**

The chemical formula of aspirin is C9H8O4. The molecular weight of aspirin is therefore 180 g/mol. To get the grams of aspirin in the problem, just multiply the moles given by the molecular weight (to cancel units). Hope this helps~ `u`
*March 17, 2015*

**math**

Represent the unknowns. Since the ratio of their money shared is 5 (David) : 2(John), Let 5x = David's money Let 2x = John's money In the problem, John received $30 less than David. Thus, 2x = 5x - 30 Solving, 2x - 5x = -30 -3x = -30 x = 10 Thus, 5x = $50 (David) 2x...
*March 17, 2015*

**Chemistry**

Since the equation is already given, we just plug in the values. It was said in the problem that the reaction should proceed 8 times faster than the original at 315 K. Thus the ratio k2/k1 = 8. R is the universal gas constant = 8.314 J/mol-K All temperatures must be absolute (...
*March 17, 2015*

**Science**

Definitely it isn't a noble gas since noble gas are stable and unreactive. They can still form compounds with other elements though. Group 15 is also group 5A (Nitrogen, Phosphorus, etc.), and Group 17 is also group 7A (Fluorine, chlorine, etc.). Elements in these groups ...
*March 17, 2015*

**Science**

Yes it's B. :)
*March 17, 2015*

**Algebra**

I think you mean x^3 - 6x^2 + 8x for the equation written in the problem. No, the answer you got isn't quite right. The first factoring is correct though. To factor x^3 - 6x^2 + 8x, the first obvious factor here is x, since all terms in the expression contain x. Thus, x(x^...
*March 17, 2015*

**Math, HELP PLEASE!**

No, it isn't. In a geometric sequence, there is a fixed number multiplied by a term to get the next term. This is an example of geometric sequence: 3, 6, 12, 24, 48, ... Here, we can see that each term is multiplied by two to get the next term. 3*2 = 6 ; 6*2 = 12, and so ...
*March 17, 2015*

**math**

I just assume you want to convert the 275 liters to mL units. To convert, note that 1 L = 1000 mL. Thus to cancel units, 275 L * (1000 mL / L) = 275000 mL hope that helps? ^^;
*March 17, 2015*

**Algebra help please**

I'm not sure if that expression is 4*sqrt(400) / (4*sqrt(5)), or the fourth root (radical sign with a number four on it). If it's the fourth root, then your answer is correct. `u`
*March 17, 2015*

**Algebra**

f(x) = x^2 + 2x - 9 This is a quadratic equation. There are plenty of ways to get its maximum/minimum. One way is to graph and locate on the graph the point where max/min occurs. Another is to solve for its vertex. We can transform the equation into the form f(x) = a(x-h)^2 + ...
*March 17, 2015*

**chem**

Recall that molarity is moles of solute per liter of solution. It has mol/L (or M) units. M = n/V First, we convert the volume (100 mL) to liters units. To convert, we just divide it by 1000: 100 / 1000 = 0.1 L Since we need to calculate the moles, we rearrange the formula to ...
*March 16, 2015*

**Chemistry**

Activated complex - a species in a transition state. (not sure about this one though) Elementary reaction - a reaction in which the stoichiometric coefficients in the balanced chemical reaction is equal to the exponents used the rate equation, or (if that isn't very clear...
*March 16, 2015*

**Chemistry**

Heterogeneous reaction - a chemical reaction in which the reactants are in different phases. Some examples are, Liquid-solid: alkylation with AlCl3 catalyst Gas-liquid: gas absorption with reaction Gas-liquid-solid: hydrogenation of liquids Homogeneous reaction - a chemical ...
*March 16, 2015*

**math**

Note that the equation is in slope-intercept form, y=mx+b where m is the slope and b is the y-intercept In the equation y=-1/3x + 3, therefore the slope is -1/3.
*March 16, 2015*

**Algebra**

To get the x-intercept, let y = 0 and solve for x: -3x + 4y = -12 -3x + 4(0) = -12 -3x = -12 x = 4 Thus x-intercept is at (4,0) To get the y-intercept, let x = 0 and solve for y: -3x + 4y = -12 -3(0) + 4y = -12 4y = -12 y = -3 Thus y-intercept is at (0,-3) hope this helps~ `u`
*March 16, 2015*

**Maths**

Average weight is the total weight divided by the number of people. To find the average weight of boys, we first look for the total weight of all (boys + girls), and the total weight of the girls. Weight of all (boys + girls): 44 * 50 = 2200 kg Weight of girls: 40 * (50 - 40) ...
*March 15, 2015*

**Calculus**

Substitute y = 3x - 7 to x^2*y: x^2 * (3x - 7) 3x^3 - 7x^2 Then differentiate with respect to x, and equate to zero (since we're looking for maximum/minimum): 9x^2 - 14x = 0 x(9x - 14) = 0 x = 0 x = 14/9 Note that if x = 0, the minimum product of x^2 * y is zero. But if x...
*March 15, 2015*

**Calculus**

*Correction* I'm sorry, the one I did is not called L'hopital's rule. That is just another technique of finding limits (dividing numerator and denominator by the variable with highest degree). L'hopital's rule is different, for it uses separate ...
*March 15, 2015*

**Calculus**

lim [ 6x^2 / (200-4x-kx^2) ] as x->infinity = 1/2 Notice that the numerator and denominator has the same highest degree of x. Therefore, we can use the L'hopital's rule. To do this, we divide both numerator and denominator by x^2: lim [ (6x^2 / x^2) / (200-4x-kx^2)/...
*March 15, 2015*

**Algebra**

(1) Yes (2) Yes (3) Hmm how did you arrive with your answer, because I'm getting, = 70 + 40 + 2(30 + .29) = 110 + 2(30.29) = 110 + 60.58 = 170.58 or perhaps there is typo or missing info? And I'm also curious with your use of 'm' units.
*March 15, 2015*

**Physics**

P,abs = P + pgh P = (1.01*10^5 Pa) + (1025 kg/m^3)*(9.8 m/s^2)(15 m) P = 101000 + 150675 P = 251675 Pa Check the significant figures. Hope this helps~ `u`
*March 14, 2015*

**Calc**

∫ (2x+1)/(x+1) dx We can separate this term into two terms by taking each term in the numerator: ∫ (2x)/(x+1) + 1/(x+1) dx For the term on the right, ∫ 1/(x+1) dx = ln |x+1| For the term on the left, Let u = x+1, thus x = u-1, and dx = du Replacing, 2 ∫...
*March 14, 2015*

**Calculus check**

Yes, that's right. `u`
*March 14, 2015*

**maths**

To get the lateral surface area, simply multiply the base perimeter by the height, 25 cm * 40 cm = ? hope this helps~ `u`
*March 14, 2015*

**chemistry**

First, we write the balanced reaction: 2 AgNO3 + K2S -> 2 KNO3 + Ag2S Recall that molarity is moles per liter solution, or M = n/V Then we get the number of moles of K2S by simply multiplying the volume (should be in L units) by the concentration (Molarity has units mol/L...
*March 13, 2015*

**Math**

(1) You have to recall some laws of exponents. 15 * 3^(y+1) - 243 * 5^(y-2) = 0 3 * 5 * 3^(y+1) - 3^5 * 5^(y-2) = 0 5 * 3^(y+1+1) - 3^5 * 5^(y-2) = 0 5 * 3^(y+2) = 3^5 * 5^(y-2) 3^(y+2) / 3^5 = 5^(y-2) / 5 3^(y+2-5) = 5^(y-2-1) 3^(y-3) = 5^(y-3) The only number that will ...
*March 13, 2015*

**Math Functions (if i have correct answer)**

Max height - yes, we got approximately the same answer Time - the time you got is the time where the ball reached the maximum height. The question asks for the total time (the time the ball is above the surface of Mercury), therefore you should multiply it by 2, so it would ...
*March 13, 2015*

**math**

f varies inversely with g: f = k * (1/g) where k is some constant. f=20 when g=4: 20 = k * (1/4) k = 20 * 4 k = 80 f=? when g=10 f = 80 * (1/10) f = 8 Hope this helps~ `u`
*March 12, 2015*

**Algebra**

an = ao + (n-1)d where an = the nth term ao = the first term n = number of terms d = difference between two consecutive terms Substituting the given, (i) a6 = 13 (here, n=6, an=13) 13 = ao + (6-1)d 13 = ao + 5d (ii) a10 = 25 (here, n=10, an=25) 25 = ao + (10-1)d 25 = ao + 9d ...
*March 12, 2015*

**chemistry**

We write the reaction: HC2H3O2 + KOH -> KC2H3O2 + H2O The products are potassium acetate (salt) and water.
*March 12, 2015*

**chemistry**

Assuming the gas is ideal, for a fixed volume of gas, we can use the Gay-Lussac Law, which states that Pressure is directly proportional to Temperature of gas: P = kT where P = pressure k = some constant T = temperature (in Kelvin) If we're given sets of values for ...
*March 12, 2015*

**math**

Recall that speed is distance traveled over time: v = d / t Rearranging to get t, t = d / v For the two trips, the distance traveled is the same, while the speed and time of travel are different. We represent each time traveled as such: Let t1 = time traveled (towards Rocky ...
*March 12, 2015*

**Separation processes**

If the "low" volatility in the question means it is CLOSE to 1 (not equal to 1), then the answer is letter 'D' or 'separation of components is difficult. If it said "exactly equal to 1", then it's 'B'. But since it doesn't ...
*March 12, 2015*

**help**

Because half-life means final amount becomes 50% of original, therefore, after another half-life time, the final amount becomes 25% of original. Well if you look at the problem, all you have to do is multiply the the half-life 12.3 years by 2, which is 24.6 years. But if you ...
*March 11, 2015*

**Math**

Represent the unknowns. Let x = length since the width is 3/4 of the length, Let (3/4)x = width Recall that the area of rectangle is just width multiplied by the length, A = w * l Substituting, 432 = (3/4)x * x 432 = (3/4)x^2 432 * 4/3 = x^2 576 = x^2 Get the square root of ...
*March 11, 2015*

**Chemistry help please**

Yes, that's right. The oxidation number of P in P2O3 is +3.
*March 11, 2015*

**Math**

This problem looks similar to the other math problem posted here. OwO Anyway, first represent the unknowns. Let x = length since the width is 2/3 of the length, Let (2/3)x = width Recall that the area of rectangle is just width multiplied by the length, A = w * l Substituting...
*March 11, 2015*

**Chemistry ( I NEED HELP, PLEASE!!!, IM DESPERATE!)**

First, we balance the chemical reaction: 2 Na2O2 + 2 H2O → 4 NaOH + O2 Then, we need to determine the molar masses of Na2O2 and O2 in order to convert them to moles. To get them, we need the mass of each element in the formula and add. In the periodic table, Na = 23 and ...
*March 11, 2015*

**algebra**

Note that an object falling freely experiences uniformly accelerated motion (UAM). In this case, we can use the formula, h = vo * t - (1/2) * g * t^2 where h = height or distance vo = initial velocity t = time g = acceleration due to gravity = 9.8 m/s^2 = 32.2 ft/s^2 Since the...
*March 11, 2015*

**Adverbs **

Which words make up the adverb phrase in this sentence? The school bus crosses two bridges along its route. A. along its route B. two bridges along C. The school bus D. crosses two bridges
*November 25, 2014*

**grovment**

General public might be swayed by a charismatic leader.
*November 25, 2014*

**intermediate math**

Recall that distance is equal to rate (or speed) mutiplied by time: d = v*t Let r = speed of Payton Let r + 4.5 = speed of Angie If they are jogging opposite to each other, then the distance between them is equal to the sum of their rates multiplied by the time: d = r*t + (r+4...
*September 29, 2014*

**chemistry**

Recall Boyle's Law: P1 * V1 = P2 * V2 where P1 = initial pressure P2 = final pressure V1 = inital volume V2 = final volume This is applicable if Temperature is held constant. Substitute the given values and solve for P2. Hope this helps~ :)
*September 28, 2014*

**Chemistry- colligative properties**

Van't Hoff factor can be associated to the property of the substance (if it's strong electrolyte, weak electrolyte, etc.), and can be approximated by counting the number of ions dissociated in water. a. i ~ 1 (weak acid, therefore weak electrolyte) b. i = 2 (strong ...
*September 28, 2014*

**Physics**

Formulas we need (uniformly accelerated motion): h = vo*t - (1/2)gt^2 vf^2 - vo^2 = 2gd Let H,t be the height of tower. The first stone thrown upward reaches its maximum height, h,max = vo^2 / 2g h,max = 15^2 / 19.6 h,max = 11.4796 meters (above the tower) and the time needed ...
*September 28, 2014*

**mathematics**

A bag contains 10 red, 15 white, 25 green balls. What should be the minimum number of balls drawn without replacement so that you get 5 red, 3 white, 10 green balls.
*September 9, 2014*

**college algebra**

A large rectangular movie screen in an IMAX theater has an area of 7200 square feet. Find the dimensions of the screen if it is 10 feet longer than the width.
*September 6, 2014*

**Calculus**

f(x)=sqrt(x^3+2) We can also rewrite this as, f(x) = (x^3 + 2)^(1/2) Then we can use chain rule, f'(x) = (1/2)*(3x^2)*(x^3 + 2)^(-1/2) Finally, the second derivative is f''(x) = (3/2)(2x)(x^3 + 2)^(-1/2) + (3/2)(x^2)(3x^2)(-1/2)(x^3 + 2)^(-3/2) And simplify. Hope ...
*May 16, 2014*

**geometry**

Recall the Pythagorean theorem: c^2 = a^2 + b^2 where c is the hypotenuse (which is also the longest side of a right triangle) and a & b are the legs. Substitute each side lengths to the equation. Of course the longest side is c, and the remaining sides are a and b. If the set...
*May 16, 2014*

**phys**

A boat is traveling upstream at 14 mph with respect to a river that is flowing at 6 mph (with respect to the ground). A man runs directly across the boat, from one side to the other, at 6 mph (with respect to the boat). The speed of the man with respect to the ground is:
*February 19, 2014*

**Math - Check my answer?**

Yes that's correct.
*January 8, 2014*

**Math check**

1. Actually it's B. Expanding, 2(x - 3) = 2x 2x - 6 = 2x -6 = 0 Note that if you get an answer like this (constant = zero), there is no solution. 2. It's D. (btw I don't know why you put question mark beside 3) Expanding, 3(y - 3) = 2y - 9 + y 3y - 9 = 3y - 9 or 0...
*January 8, 2014*

**algebra**

Let A = number of sweets of Alvin Let C = number of sweets of Calvin Let M = number of sweets of Melvin According to the statements, A < C A + C = 31 M = A + 24 Note that to maximize M, A should also be maximized. Maximum value of A is 31 (that is, if C = 0), but according ...
*December 30, 2013*

**geometry**

Recall that surface area of cone is SA = pi*r^2 + pi*r*s where r = radius s = slant height Substituting, SA = 3.14 * 15^2 + 3.14 * 15 * 11 SA = 706.5 + 518.1 SA = 1224.6 sq units Hope this helps :3
*December 29, 2013*

**MATHS**

Area of disc (circle): A = pi*r^2 A = 3.14 * 7^2 A = 153.86 cm^2 Area of cardboard (rectangle): A = L * W A = 70 * 50 A = 3500 cm^2 Divide area of rectangle by area of circle: 3500 / 153.86 = 22.75 Take only the whole number: 22 discs Hope this helps :3
*December 29, 2013*

**Genius Math**

Hmm, the triangle seems impossible, because if you draw it, given the condition that AC = BC (thus it's an isosceles triangle), then angle ACB = 96, therefore BAC = 96 degrees also (since the sides opposite to the angles are equal). So if there are two angles which are 96...
*December 24, 2013*

**Chemistry**

When naming alkanes, alkenes, alkynes, yes, it's the longest chain that is first counted. And then identify the groups attached to to. (For instance methyl, ethyl, etc). Then number the carbon in the longest chain, starting from the nearest attached group (if it's ...
*December 21, 2013*

**Mechanics**

Recall that Pressure is just Force over a unit Area, or P = F/A We are given the force (which is 220 N), therefore, we only need to find area. A = L*W A = 4*3 = 12 m Therefore, P = 220 / 12 P = 18.33 N/m^2 P = 18.33 Pa Hope this helps :3
*December 21, 2013*

**math**

Find the value of df^-1/dx at x=f(a). f(x)=5x+8, a=-1 i got 5?
*December 19, 2013*

**science**

That's correct. :)
*December 18, 2013*

**Algebra 1**

Let x = weight of chicken in pounds Let y = total cost of x pounds of chicken Therefore, y = 2.99x To see the graph of this, go to wolframalpha . com and type in the equation. Hope this helps :3wol
*December 18, 2013*

**math**

f(x) = 7x - 2
*December 18, 2013*

**algebra**

Substitute T = 141 to the equation: 141 = –0.005x^2 + 0.45x + 125 Simplify: –0.005x^2 + 0.45x + 125 - 141 = 0 –0.005x^2 + 0.45x - 16 = 0 Recall that discriminant is just D = b^2 - 4ac if D < 0 : imaginary root D = 0 : real, equal root D > 0 : two real, ...
*December 18, 2013*

**Pre-Calculus**

*I mean you get all the factors of x = +/- p/q. In the problem, x = +/- 20, and its factors are written there above. The factors are the ones you have to check by substituting them to the expression. :)
*December 16, 2013*

**Pre-Calculus**

You use rational root theorem. Let p = constant term Let q = numerical coefficient of highest degree of x x = +/- p/q In here, p = -20 and q = 1. Thus, x = (+/-) 1 , 2 , 4 , 5 , 10, 20 You have to substitute each factor (for instance x = -1) to the expression, and if you get a...
*December 16, 2013*

**Math Quick Question**

You spoke to that person for 45 minutes only.
*December 8, 2013*

**Chemistry(DrBob222)**

Yes, that's right. :)
*December 8, 2013*

**math**

1/13 = 0.0769230769230... The repeating numbers are 076923 (six numbers), thus, 43 / 6 = 7 remainder 1. Therefore counting from zero, the 43rd digit after the decimal point is 0. hope this helps. :3
*December 7, 2013*

**Math**

1. No 2. Parallel
*December 7, 2013*

**Math**

x + 7 ≥ 3x x - 3x ≥ -7 -2x ≥ -7 x ≤ 7/2 x ≤ 3.5 3x + 4 ≤ 5x 3x - 5x ≤ -4 -2x ≤ -4 x ≥ 2 Therefore, the common solution is from 2 to 3.5, or 2 ≤ x ≤ 3.5 Hope this helps :3
*December 7, 2013*

**algebra**

d = 0.05r^2 + r Substitute r = 45: d = 0.05(45)^2 + 45 d = 101.25 + 45 d = 146.25 ft To the nearest foot, d = 146 ft Hope this helps :3
*December 7, 2013*

**math**

h(n) = 100 / 9 n Substitute n = 27: h(27) = (100 / 9) * 27 h(27) = 100 * 3 h(27) = 300 dollars hope this helps :3
*December 7, 2013*

**math**

12 - q ≥ -13 Just solve it like a true equation: 12 + 13 ≥ q 25 ≥ q or q ≤ 25 Hope this helps :3
*December 7, 2013*

**Chemistry**

Formula to be used: Molality = moles of solute / kg solvent Steps: #1. To do this, get the molar mass of Tin, using a periodic table. Fomula for Tin in Sn (look it up in the periodic table, and you'll see its mass). #2. After you get the mass of Tin, divide it by 5 g, and ...
*December 4, 2013*

**Chemistry**

*repost* Formula for osmotic pressure: Π = MRT * i where m = molarity (mol solute / L solution) R = universal gas constant = 0.0821 L-atm/mol-K T = temperature (K) i = van't Hoff factor (approximately equal to ionizable ions) Note that sucrose is soluble in water, but...
*December 4, 2013*

**Chemistry**

Formula for osmotic pressure: Π = MRT * i where m = molarity (mol solute / L solution) R = universal gas constant = 0.0821 L-atm/mol-K T = temperature (K) i = van't Hoff factor (approximately equal to ionizable ions) Note that sucrose is soluble in water, but does not...
*December 4, 2013*

**Algebra 1**

Yes, your answer is correct. :) (I thought at first the radius is 2 and 1/2, not 21/2, but I guess that's too small) :3
*December 4, 2013*

**Geometry**

Use Heron's formula. Let a, b and c be the sides of a triangle. Let s = a + b + c Therefore the area of triangle can be calculated using this formula: A = sqrt[ (s)(s-a)(s-b)(s-c) ] It should be a little easy using this formula, so I guess you can do it on your own. :) ...
*December 4, 2013*

**Calculus**

limit (sin(4x+12))/(5x+15) as x -> -3 If we try substituting, = (sin(4(-3)+12))/(5(-3)+15) = sin(-12+12) / -15+15 = sin(0) / 0 = 0 /0 Note that 0/0 is indeterminate, and if you arrive at this answer, you use the L'hopital's rule. To use the L'hopital's rule...
*December 2, 2013*

**Physics**

You can use the formula for Uniformly Accelerated Motion (UAM): h = (v,o)t - (1/2)gt^2 Or you can use another formula, which does not use time: v,f^2 - v,o^2 = 2gd where v,f = final velocity v,o = initial velocity g = acceleration due to gravity = 9.8 m/s^2 d = distance (in ...
*December 1, 2013*

**math**

1. Yep 2. The remaining distance is is 120 - 60 = 60 miles (because the first 60 miles was already covered in 1.2 hours according to #1) Speed is distance over time, or v = d/t Substituting, 40 = 60/t t = 60/40 t = 1.5 hours 3. Yep
*December 1, 2013*

**math**

Let x = multiplier. Thus, Men = 7x Women = 5x The ratio of men to women is still 7 to 5. Since there are 440 more men than women, we can say that 7x = 5x + 440 Solving for x, 7x - 5x = 440 2x = 440 x = 220 The total men and women is 7x + 5x = 12x. Thus the total is, total = ...
*December 1, 2013*