Friday

January 20, 2017
Total # Posts: 13,044

**Math**

42 < -6d. -7 > d. or d < -7.

*January 11, 2016*

**physics**

a = (V-Vo)/t. Initial Momentum = M*Vo. Final momentum = M*V. Change in momentum = M*V-M*Vo. F = M*a.

*January 11, 2016*

**Math**

See previous post.

*January 11, 2016*

**Math**

Multiply Eq1 by -2 and add: Eq1: -3x - 4y = -22. Eq2: +3x + 6y = 22. Sum: 2y = 0. Y = 0. In Eq2, replace y with 0 and solve for x: 3x + 6*0 = 22. X = 7 1/3. One solution.

*January 11, 2016*

**Math Check (thanks)**

1. 6/(4*5) = 6/20 = 3/10 = 30%. 3. 19/25 = 0.76 = 76%. 4. 0.09 * 100% = 9%. 5. 37.1%/100% = 0.371. 6. 0.8 = 80%; 7/8 = 87.5%. 19/25 = 0.76 = 76%. Order: 19/25, 0.8, 81%, 7/8. 7. (165/250) * 100% = 8. (4/15) * 100% = 9. (52/5) * 100% = 10. 365%/100% = 3.65 = 3 13/20. 11. 100...

*January 11, 2016*

**Math**

A semicircular shape is in a (fills it) rectangle. If the perimeter of the rectangle is 30 cm, fine the perimeter of the semicircular shape.

*January 11, 2016*

**Algerbra**

y + 4x = 3. y + 4*(-1) = 3. Y = 7. (-1,7). y + 4*5 = 3. Y = -17. (5,-17).

*January 10, 2016*

**Physics**

Vo = 100m/s[30o]. Yo = 100*sin30 = 50 m/s. Y^2 = Yo^2 + 2g*h. h = (Y^2-Yo^2)/2g + ho. y = 0. g = -9.8 m/s^2. ho = 100 m. h = ?

*January 10, 2016*

**math**

(-6,1), (-3,2). m = (2-1)/(-3-(-6))/ = 1/3. Y = mx + b. (1/3)(-6) + b = 1. -2 + b = 1. b = 3. Y = (1/3)x + 3.

*January 10, 2016*

**maths**

T1*T2/(T1+T2) = T3. T1*(T1-10)/(T1+(T1-10)) = T1-18. (T1^2-10T1)/(2T1-10) = T1-18. Multiply by 2T1-10: T1^2-10T1 = 2T1^2-36T1-10T1+180 -T1^2 + 36T1 - 180 = 0 T1^2 - 36T1 + 180 = 0. -6*-30 = 180, -6 + -30 = -36 = B. (T1-6)(T1-30) = 0. T1-6 = 0, T1 = 6 h. T1-30 = 0, T1 = 30 ...

*January 10, 2016*

**maths**

T = Ta*Tb/(Ta+Tb) = 40*30/(40+30)= 17.14 Min. to fill with both pipes open. (17.14-5)/17.14 = 0.708 of a tank to be filled. 5 + 0.708*40 = 33.34 Min., total.

*January 10, 2016*

**Math**

400qts. = 1600 Cups. 400qts < 4000 Cups. or 4000Cups > 400qts.

*January 10, 2016*

**Math**

400qts * 32oz/qt * 1cup/8oz = 1600 Cups.

*January 10, 2016*

**Math**

X > c-b.

*January 10, 2016*

**physics**

Unless otherwise stated, all angles are measured CCW from the +x-axis. D = -120 + 210[315o] + 280[60o]. X = -120 + 210*Cos315 + 280*Cos60 = 168.5 m. Y=210*sin315 + 280*sin60 = 94 m. Tan A = Y/X = 94/168.5 = 0.55786 A = 29.2o D = X/Cos A = 168.5/Cos29.2 = 193 m[29o]. b. ...

*January 9, 2016*

**physics**

610MW = 610MJ/s. a. Energy = 610MJ/s * 3600s/h * 24h/day * 30days = 1.581*10*9 MJ.

*January 9, 2016*

**math**

I = Ab*r*t=749.25*(0.12/360)*120 = $29.97 Ar = Ab-I=749.25 - 29.97=$719.28 = Amount received(proceeds). I = Interest. Ab = Amt. borrowed. Ar = Amt. received.

*January 8, 2016*

**1 math question**

Correct.

*January 8, 2016*

**Calculus**

A water tank is made by rotating f(x)=2^x-1 between [0,2] about the y-axis. The water tank is initially full, when a hole is opened at the bottom tip so that the water drains at a rate of 4 unit^3/second. How fast is the height of the water decreasing when the height has ...

*January 8, 2016*

**Math**

2. T-((T/2)-6 + (T/3)-2) = T-((3T/6)-6 + (2T/6)-2) = T - ((5T/6) - 8) = T - 5T/6 + 8 = 6T/6 - 5T/6 + 8 = T/6 + 8.

*January 7, 2016*

**Math**

1. #1. m. #2. 2m-1. #3. 4m-2-1 = 4m-3. #4. 8m-6-1 = 8m-7. #5. 16m-14-1 = 16m-15. #6. 32m-30-1 = 32m-31. m + 2m-1 + 4m-3 + 8m-7 16m-15 + 32m-31 = 63m - 57.

*January 7, 2016*

**Physics-Conservation of Momentum**

V1 = 90km/h = 90000m /3600s = 25 m/s. V = 80km/h = 80000m/3600s = 22.2 m/s. M1*V1 + M2*V2 = M1*V + M2*V. M1*25+6000*0=M1*22.2 + 6000*22.2 25M1-22.2M1 = 6000*22.2. 2.78M1 = 133,200. M1 = 47,952 kg. = 4.8*10^4 kg.

*January 7, 2016*

**Maths**

(2/3)*3.14*(30/2)^3=3.14*r^2*22.5 7069 = 70.69r^2. r^2 = 100. r = 10 cm.

*January 7, 2016*

**Math**

1. D = 200[115o] + 150[230o]. X = 200*Cos115 + 150*Cos230 = -181 km. Y = 200*sin115 + 150*sin230 = 66.4 km. D = Sqrt(X^2 + Y^2) = Distance from C to A. Tan A=Y/X = 66.4/-181 = -0.36685 A = 20.1o N. of W. = 159.9o CCW. = Bearing.

*January 7, 2016*

**Math**

Vc = 12*18*6 = 1296 in^3. Vb = 4*6*2 = 48 in^3. Vc/Vb = 1296/48 = 27 Boxes.

*January 6, 2016*

**ALGEBRA**

9m/2 - 6 = -7/2 + 4m. Multiply both sides by 2: 9m - 12 = -7 + 8m. 9m - 8m = 12 - 7. m = 5.

*January 6, 2016*

**area perimeter**

2L + 2W = 28. Divide both sides by 2: Eq1: L + W = 14. Eq2: L*W = 24. L = 24/W. In Eq1, replace L with 24/W: 24/W + W = 14. Multiply both sides by W: W^2 + 24 = 14W. W^2 - 14W + 24 = 0. 24 = -2*-12, -2 + -12 = -14 = B. (w-2)(w-12) = 0. w-2 = 0, W = 2. w-12 = 0, W = 12. (L,W) (...

*January 6, 2016*

**Typo (Test Marked)**

1. N = 0.73 * 215 = 156.95 2. 23/94 = 0.2447 = 24.47%. 3. 80 = 0.40*N. N = 200. 4. C = 0.05 * 1250 = $62.50 5. 100% + 6% = 106% = 1.06 Total Cost = 1.06 * 325 = $344.50

*January 6, 2016*

**pre-algebra**

1. Do you mean (y-5)/3 = 1 ? If so, y-5 = 3, Y = 8. If you mean y - 5/3 = 1, The answer is 8/3 or 2 2/3(Ms Sue's answer). Without the parenthesis, the tutor don't know what you mean ; because their are 2 possibilities.

*January 6, 2016*

**Algebra**

(4,-2), (0,-4). m=(-4-(-2))/(0-4) = -2/-4 = 1/2. Y = mx + b = -2. (1/2)4 + b = -2. 2 + b = -2. b = -4. Eq: Y = (1/2)x - 4.

*January 6, 2016*

**Math**

x-2y = 0. 2y = x. y = (1/2)x. Slope = 1/2 = Tan A. A = 26.57o. Cos 26.57 = 0.89443.

*January 6, 2016*

**Algebra**

m = (-5-r)/(3-1) = -4. (-5-r)/2 = -4. Multiply by 2: -5-r = -8. r = 3.

*January 5, 2016*

**Algebra**

Correct!

*January 5, 2016*

**Algebra**

Correct.

*January 5, 2016*

**Algebra.**

To break even: Income = Expense. 5x + 1300 = 3x + 1800 + 1500. 5x - 3x = 1800 + 1500 - 1300. 2x = 2000. X = 1000 Tickets.

*January 5, 2016*

**Algebra**

P = 2L + 2W. W = L. P = 2L + 2L = 4L. 20< P < 94. 20< 4L < 94. Divide by 4: 5< L < 23.5 in. 5< W < 23.5 in.

*January 5, 2016*

**Algebra 1**

1. (-3,2).

*January 5, 2016*

**Algebra 1**

Correct.

*January 5, 2016*

**Algebra 1**

Eq1: 4x + 2y = 10. Eq2: Y = -3x + 6. In Eq1, replace y with -3x+6 and solve for x: 4x + 2(-3x+6) = 10. 4x - 6x + 12 = 10. -2x = -2. X = 1. In Eq2, replace x with 1 and solve for y: Y = -3*1 + 6 = 3. Solution: (1,3).

*January 4, 2016*

**Algebra 1**

None of the give answers satisfy BOTH of the given equations. Remember that each answer must satisfy BOTH equations. My answer: (-2/3,-77/3) satisfies BOTH equations.

*January 4, 2016*

**Algebra 1**

Eq1: 4x - y = 23. Eq2: 7x - y = 21. Multiply Eq2 by -1 and add: +4x - y = 23. -7x + y = -21. Sum: -3x = 2. X = -2/3. In Eq1, replace x with -2/3 and solve for y. 4(-2/3) - y = 23. Y = ? You should get: Y = -77/2 = -25 2/3.

*January 4, 2016*

**Algebra 1**

Eq2: y + 4 = -3x. Y = -3x - 4. Eq1 and Eq2 are identical. Therefore, there are an infinite number of solutions. The graph is a single line.

*January 4, 2016*

**algebra 1**

A. Correct. B. In Eq1, replace x with 30+y and solve for y: 30+y + y = 60. 2y = 30. Y = 15 Minutes on free hand exercises. C. Yes, but the time spent in the gym would be 55 minutes(15+40) instead of 60 minutes.

*January 4, 2016*

**math**

7256chickens * 3290feathers/chicken = 23,872,240 Feathers to be plucked. 23,872,240fe * 2.6s/83.6fe * 1h/3600s = 206.2 h.

*January 4, 2016*

**Math**

Unless otherwise indicated, all angles are measured CCW from +x-axis. Ship #1: d1 = 11.5km/h[52o] * 2h = 22km[52o]. Ship #2: d2 = 13km/h[ 317o] * 2h = 26km[317o]. d2-d1 = 26[317o] - 22[52o]. X = 26*Cos317 - 22*Cos52) = 5.47 km. Y = 26*sin317 - 22*sin52 = -35.1 km. d2-d1 = Sqrt...

*January 3, 2016*

**physics**

V = Vo + a*t = 0. a = -Vo/t = -3/5 = -0.6 m/s^2.

*January 2, 2016*

**Calculus**

Okay I didn't know you could do that haha

*January 2, 2016*

**Calculus**

Wait, but how can you let u=x^3 when there is not an x^3 in the equation

*January 2, 2016*

**Calculus**

Last one for me. Evaluate (3x^2)/sqrt(1-x^6) dx I changed sqrt (1-x^6) into 1^(1/2)- x^(3) and let u=1^(1/2)- x^(3) then I got du/dx=3x^2 and subbed dx=du/3x^2 into the equation and got x-(x^4/4) but its not right. Options 7x^3/(3sqrt(1-x^7) + C cos-1(3x) + C sin-1(x^3) + C ...

*January 2, 2016*

**Calculus**

Im think im going to go with B then

*January 2, 2016*

**Calculus**

Okay Thanks. That one confused me.

*January 2, 2016*

**Calculus**

Okay will do. So I'm presuming your saying the answer is B. I think D works.

*January 2, 2016*

**Calculus**

Wait so A is right or is it wrong?

*January 2, 2016*

**Calculus**

Which of the following integrals cannot be evaluated using a simple substitution? I think it is A because if you would substitute there would be nothing left in the equation? Is that right? Options ∫√(x-1) ∫1/√(1-x^2) ∫x/√(1-x^2) ∫&#...

*January 2, 2016*

**Calculus**

Oh shoot I misread my answer. Thanks

*January 2, 2016*

**Calculus**

∫(x^3-x^2)/x^2 I got (x^2)/(2)-x + C but that's not one of the answers Options x - 1 + C (x^2/2)-(x^3/3) + C (x^4-x^3)/4x^2 + C (x^2/2) -x + C

*January 2, 2016*

**Calculus**

Yes Thank you

*January 2, 2016*

**Calculus**

∫((cos^3(x)/(1-sin^(2)) What is the derivative of that integral? I have been trying to use trig identities but can't find one to simplify this equation. I can't find one for (cos^3(x) or (1-sin^(2)) My options -sin(x) + C sin(x) + C (1/4)cos^(4)(x) + C None of ...

*January 2, 2016*

**Math**

Yes, it is I, your humble servant(LOL).

*January 1, 2016*

**Math**

T = 2 h. Ta = 3 h. Tb = ? T = Ta*Tb/(Ta+Tb) = 2. 3*Tb/(3+Tb) = 2. Tb = ?.

*January 1, 2016*

**Physics**

F = M*a, M = F/a = 26.5/6.5.

*January 1, 2016*

**English**

I chose C

*January 1, 2016*

**Maths**

g Girls in the class. 4g + 3 Boys in class. Total = g + (4g+3). The total should have been given.

*December 31, 2015*

**physics in kinematics**

Vo = 18m/s[37o]. Xo = 18*Cos37 = m/s. Yo = 18*sin37 = m/s.

*December 30, 2015*

**Physics**

A. Vr = -104 - 398i = 411.4km/h[75.4o] S. of W. = 14.6o W. of S. B. 411.4km/h[14.6o] E. of S.

*December 29, 2015*

**Science**

V^2 = Vo^2 + 2a*d = 0 + 2*0.5*100 = 100. V = 10 m/s. V=10m/s * 1km/1000m * 3600s/h = 36 km/h.

*December 29, 2015*

**physics**

Fr = 10N.[0o] + 30N.[120o] + 50N.[240o] X = 10 + 30*Cos120 + 50*Cos240 = -30 N. Y = 30*sin120 + 50*sin240 = -17.3 N. Tan A = Y/X = -17.3/-30 = 0.57735. A=30o S. of W. = 210o CCW from +x-axis. Fr = -30/Cos210 = 34.64 N. @ 210o CCW.

*December 28, 2015*

**PHYSICS**

Fr = Sqrt(F1^2 + F2^2) = Resultant force

*December 28, 2015*

**Calculus**

I tried to use partial fractions to do it, but it didn't work.

*December 27, 2015*

**Calculus**

Find the integral of 2/((2-x)(x+2)^2)dx.

*December 27, 2015*

**Physics**

I = (5^2/20^2)*X = (1/16)X W/m^2.

*December 26, 2015*

**Precalc**

The "j" means there is a 90-degree phase difference between the two terms and they cannot be added directly. Another method of writing the polar form: 2.83[45o].

*December 26, 2015*

**physics**

Work = F*d = 1500*Cos60 * 30 =

*December 26, 2015*

**Calculus**

Solve the following problem by separation of variables. T^2y'-t=ty+y+1 Y(1)=0 Y is a function of t.

*December 25, 2015*

**Calculus**

Wait, why is it the integral from 3-5 instead of 0-2?

*December 23, 2015*

**Calculus**

Sorry I forgot the dx after the integral.

*December 23, 2015*

**Calculus**

Find the integral from 0 to 2 of xsqrt(5-sqrt4-x^2)). The hint said to use substitution of u=sqrt(4-x^2), and that I needed one more substitution, but I don't know how to do it.

*December 23, 2015*

**Algebra 1**

Since there are 2 variables and only 1 Eq, I have to solve for 1 variable in terms of the other.

*December 23, 2015*

**Algebra 1**

12AB + 7B = 5A. 12AB - 5A = -7B. A(12B - 5) = -7B. Divide by (12B-5): A = -(7B/(12B-5)).

*December 23, 2015*

**physics**

Glad I could help.

*December 23, 2015*

**physics**

By definition, acceleration means to increase speed. When speed is decreasing it is called Deceleration. So you can't do both at the same time. When an object is moving, it is either accelerating, decelerating or moving at a constant speed. In other words, there are 3 ...

*December 23, 2015*

**physics**

d = 75N * 1m/1500N = 0.05 m. PE=0.5F * d = 0.5*75 * 0.05 = 1.875 J.

*December 21, 2015*

**physics 1**

1a. V = Vo + a*T1 = 0. T1 = -Vo/a = -22.5/-3.95=5.70 s To stop. V = Vo + a*T2 = 22.5. T2 = (22.5-Vo)/a = (22.5-0)/4.91=4.58 s. To accelerate back up to speed. T1+45+T2 = 5.70 + 45 + 4.58 = 55.3 s. 2. Hare: r*t = 1000. 1.5t = 1000. t = 666.67 s., Non-stop. Tortoise: r*t = 1000...

*December 20, 2015*

**physics**

Assuming the 3.5 m/s is horizontal: h = 0.5g*t^2. g = 9.8 m/s^2. t = ? A3. h = Vo*t + 0.5g*t^2 h = 230 m. Vo = -7.9 m/s(plane moving upward). g = 9.8 m/s^2. t = ? K5. The problem doesn't say what the captain is trying to do.

*December 20, 2015*

**physics**

Ma*Va + Mb*Vb = Ma*V + Mb*V. 30.7*2.64 + 109*1.29i + 30.7V + 109V. 81.05 + 140.6i = 139.7V. 162.3m/s[60o] = 139.7V. V = 1.16m/s[60o] N. of E.

*December 20, 2015*

**physics**

M1*V1 + M2*V2 = M1*V + M2*V. 2864*V1 + 856*0 = 2864*7.5 + 856*7.5. V1 = ?

*December 20, 2015*

**physics**

M1*V1 + M2*V2 = M1*28.7 + M2*V. 0.192*44.4 + 0.459*0 = 0.192*28.7 + 0.459V. V = ?

*December 19, 2015*

**physics**

M1*V1 + M2*V2 = M1*(-0.43) + M2*V. 0.13*0.22+0.22*(-0.30)=-0.43*0.13 + 0.22V. V = ? Multiply your answer by 100 to convert to cm/s.

*December 19, 2015*

**physics**

M1*V1 + M2*V2 = M1*V + M2*25. 24.9*22 + 13.2*11.8 = 24.9V + 13.2*25. V = ?

*December 19, 2015*

**physics**

M1*V1 + M2*V2 = M1*V + M2*V. 13.2*6.8 + 3*(-3.5) = 13.2V + 3V. V = ?

*December 19, 2015*

**physics**

a. V = Vo + g*t = 0. Vo - 9.8*2 = 0. Vo = 19.6 m/s. b. h = Vo*t + 0.5g*t^2. g = -9.8 m/s^2. t = 2 s. h = ?. c. Tr+Tf = 2 + 2 = 4 s. To fall back to top of bldg. Tr = Rise time. Tf = Fall time. 8-4 = 4 s. To fall from top of bldg. to gnd. h = Vo*t + o.5g*t^2. Vo = 19.6 m/s. t...

*December 18, 2015*

**MATH HELP**

A = (3)^5/2 * (3)^5/2 = (3)^10/2 = 3^5 = 243 in^2.

*December 17, 2015*

**College Algebra**

1. P1 = 0.64 + 0.30*0.64 = P2 = 0.64 + 0.40*0.64 = P3 = 2. P = 0.64 + m*0.64 = 1.10 0.64m = 1.10 - 0.64 = 0.46. m = 0.719 = 71.9%.

*December 17, 2015*

**Math**

A = 2*(15*5) + 2(30*5) + 30*15=900 Ft^2. = Total area to be painted. 900Ft^2 * 1gal/250Ft^2 = 3.6 Gal. of paint needed. Buy 4-1gal. cans.

*December 17, 2015*

**PHYSICS! Really Confused! Test Tmrw**

V^2 = Vo^2 + 2g*h = 0. h = -Vo^2/2g + 10 = -(5^2)/-19.6 = 11.28 m. h = 0.5g*T^2 = 11.28 m. 4.9T^2 = 11.28. T^2 = 2.30. T = 1.52 s. d = Vt*T = 30 * 1.52 = 45.6 m.

*December 17, 2015*

**Math**

(Y+1)+4

*December 16, 2015*

**physics**

See previous post: Wed,8-12-15, 12:14 AM.

*December 16, 2015*

**physics**

Correction: r = (d1+d2)/(43.3+T) = 1.99. (170.2+1.13T)/(43.3+T) = 1.99. Solve for T.

*December 16, 2015*

**physics**

d1 = 3.93m/s * 43.3s = 170.2 m. d2 = 1.13*T. r = (d1+d2)/T = 1.99 m/s. (170.2+1.13T)/T = 1.99. Multiply by T: 170.2 + 1.13T = 1.99T. 1.99T - 1.13T = 170.2. 0.86T = 170.2. T = 198 s.

*December 16, 2015*

**=**

Diode Connected: Vd + (I2+Id)R1 = 6 Volts. 0.7 + (I2+1.0)R1 = 6. 0.7 + I2*R1 + R1 = 6. Eq1: I2R1 + R1 = 5.3. Diode disconnected: V2 + I2*R1 = 6 Volts. 2 + I2R1 = 6. Eq2: I2R1 = 4. In Eq1, replace I2H1 with 4: 4 + R1 = 5.3. R1 = 1.3k = 1300 Ohms. In Eq2, replace R1 with 1.3k: ...

*December 16, 2015*