Monday

November 30, 2015
Number of results: 1,168

**Calculus 2**

Evalute the integral of x/(x^2+4)dx using u-substitution and then trigonometric substitution. I did this and got (1/2)ln(x^2+4)+C using u-substitution and x^2+4+C using trigonometric substitution. What did I do wrong??? thank you for helping!
*October 10, 2012 by Heather*

**Trigonometric Substitution**

Trigonometric Substitution a. Explain why the substitution x = asin(Theta) guarantees that cos(Theta) is greater than or equal to 0 . b. What sort of restriction must we put on x and a so that the substitution x = asec(Theta)will guarantee that tan(Theta) is greater than or ...
*June 28, 2011 by John*

**calculus**

Integrate x/(x^2 + 4) dx via trig substitution and by u=x^2+4 substitution. Show that results are equal. Via trig substitution of x=2 *tan t, I get: 1/2 * tan^-1 (x/2) + c Via u = (x^2 + 4) substitution, I get: 1/2 * ln |x^2 + 4| + c How are these equal?
*December 31, 2007 by mathstudent*

**calculus**

We're doing indefinite integrals using the substitution rule right now in class. The problem: (integral of) (e^6x)csc(e^6x)cot(e^6x)dx I am calling 'u' my substitution variable. I feel like I've tried every possible substitution, but I still haven't found the right one. The ...
*May 2, 2009 by Joshua*

**calculus**

Evaluate the following integrals using the given substitutions. (a) (3x^2 + 10x)dx/(x^3 + 5x^2 + 18 , substitution u = x3 + 5x2 + 18; (b)(14x + 4)cos(7x^2 + 4x)dx,substitution u = 7x^2 + 4x.
*May 27, 2014 by Carrolyn*

**Algebra II**

Use synthetic substitution to find f(-3) for f(x) = 2x^3 - 6x^2 - 5x + 7. _3|2 -6 -5 7 6 36 93 ______________ 2 0 31|100 then I used direct substitution and just plugged -3 in for x and the final answer is f(-3) = 86
*March 3, 2008 by Jon*

**algebra**

i need help with these problems (either a solution or how to plug them into a graphing calculator): 1) Solve by substitution or elimination 4/x + 1/y + 2/z = 4 2/x + 3/y - 1/z = 1 1/x + 1/y + 1/z = 4 2)Solve the system of equations by substitution. x^2 + y^2 = 25 x - y = 7 3) ...
*April 5, 2011 by Alyssa*

**Geometry**

Substitution Property of Equality: If a=20, then 5a= _____. The substitution rule states that If a=b then a can be substituted for b in any equation or expression. So I think that 5a=5b but the number answer is 100. Am I correct?
*October 2, 2013 by David*

**Calculus/Substitution**

The integral from 1 to 2 of x*the square root of (x-1) dx. Using the substitution method, I said that u = x-1, du = 1 dx, and dx = du. I'm not sure how to plug u back into the equation since I still have that first x. Suggestions are greatly appreciated.
*July 12, 2009 by Amy*

**math**

int 1/ (sq rt (4sec^2 x +4)) dx trigonometric substitution expression: sq rt (x^2-a^2) substitution: x=a sec x identity: sec^2 x -1=tan^2 x
*March 4, 2010 by maggie*

**algebra**

use the Substitution Method. Please give it a try. y = 3x + 4 5x + 3y = 12 Why is the substitution method preferred in this case?
*April 5, 2011 by Maya*

**Algerbra 1 substitution method**

im really confused about this question: 2x-3y=21 y=3-x using substitution method. please help
*January 31, 2012 by Austin *

**substitution **

solve by the substitution method 3x+5y=21 x=51-9y
*October 12, 2010 by Sam*

**substitution **

solve by the substitution method 3x+5y=21 x=51-9y
*October 12, 2010 by Sam*

**math**

solve each system of equations by substitution. y=3x-9 please help explain how to solve this using substitution.
*May 12, 2009 by eliza*

**Algebra**

Solve: 3x-2y=10 2x+3y=-2 Graph: Substitution: Elimination: Show Your work! (I can'tfigure out how to graph it and when i used substitution and elimination it came out with two different anwsers. I got (13/3.5,19/10.5) for substitution, and ((0.2,-0.8) for Elimination.I need ...
*January 17, 2011 by Darryl*

**calculus**

Decide on what substitution to use, and then evaluate the given integral using a substitution. HINT [See Example 1.] (Round your decimal coefficients to four decimal places.) x/(2x^2-1)^0.4 dx
*May 2, 2011 by patrick*

**Calculus**

Obtain the MacLaurin series for 1/(2-x) by making an appropriate substitution into the MacLaurin series for 1/(1-x). ------------ The MacLaurin series for 1/(1-x) = Σ x^k I substitue (x-1) in for x, because 1/(2-x) = 1/(1-(x-1)) Making the same substitution in the ...
*June 25, 2009 by Sean*

**Brief Calculus**

Decide on what substitution to use, and then evaluate the given integral using a substitution. HINT [See Example 1.] (Round your decimal coefficients to four decimal places.) x/(2x^2 − 1)^0.4 dx
*May 2, 2011 by Ashley*

**Math**

1. Explain the advantages and disadvantages of both the substitution method and the elimination method for solving a system. Help please. The only reasons I can think of is because in substitution it might be more difficult cause there's a possibility of working with fractions.
*February 18, 2008 by Amanda*

**Algebraic Systems**

Okay i just wanna know what you think is the easiest between substitution and elimination/combination. I hate elimaination becuase i get confused quicker with this when actually solving it than in substitution, but it's actually easier for me. Still, substitution is what i ...
*January 25, 2009 by <3Medic+Droid<3*

**calculus -- PLEASE HELP!**

Suppose you are trying to evaluate the intergral 2x^3dx and you make the substitution u=x^2. The substitution takes one area and converts it to a different one-in this case a trapezoid with vertical sides. Denote by R the region under the first curve from 3 to 3.01 and ...
*January 30, 2008 by anonymous*

**calculus-integration!**

should i use substitution?? if yes how should should i use it? plz i need some directions? k plz someone?...so far i used trig. substitution. i got a=8, so i used x=asin(è)so according to this substitution i got x=8sin(è) and dx=8cos(è) dè...then i used used the plug them in ...
*May 6, 2007 by Maria*

**substitution method**

Solve by substitution method please help me solve this. I do not know how to do this at all. The question is 3x+8y=33 and x=31-6y I know that I have to plug x into the first x like 3(31-6y)+ 8y = 33 but i do not know what to do from there.
*October 27, 2010 by anonymous *

**math substitution method**

use the substitution method to solve 7x+5y=-26 x=28-6y
*March 28, 2010 by KiKi*

**math/ elimination& substitution**

how do i solve this? using elimination or substitution? 2x-3y=-1/12 y=-x+7/12
*May 16, 2013 by Keyshia*

**calculus**

Help with an integration question with the substitution given? Please help, i tried to to answer it but the working is too complicated can anyone help out there, the question says: Using substitution 5x=4cosØ to show ∫ √ (16-25x^2) dx = 4 π + 6√ 3 / 15
*September 22, 2012 by Fatima*

**Math**

Calculate the integrals by partial fractions and using the indicated substitution. Show the results you get are the same. dx/1-x^2; substitution x= sin pheta I understand how to do the partial fraction part, but not the second part and I dont know how they are similar. Any ...
*February 25, 2008 by Jessica*

**O.Chem**

Only a substitution product is obtained when the compound 1-bromo-2,6-dimethylcyclohexane is treated with sodium methoxide. Draw the substitution product and explain why an elimination product is not obtained.
*November 21, 2010 by Lily*

**Algebra 1**

bobpursey, In this problem you helped me with earlier: Solve using any appropriate method. y = 2× - 5, y = ½× + 1 Substitution, substitute for y. 2×-5=½ × + 1 3/2 x=6 x=4 y= 2*4-5=3 How did you choose which method you were going to use between substitution and elimination? ...
*January 3, 2015 by slomo*

**algebra 1**

I was just wondering if anybody could explain to me the steps in 'solving systems in substitution' and 'solving systems in substitution with a variable'. I'm majorly confuzled!!!! It might help to post a specific problem so someone can show you the steps.
*March 7, 2007 by Otoño*

**Calculus**

Let f(x)=cosxsqrt(1+sinx). A. Let F(x)=the integral of f(x)dx and F(0)=5/3, find F(pi/2). I got 3.386 with U-substitution B. If G(x)=the integral of f(x)sinxdx and G(0)=1/3, find G(x). I got a reply to this but I did not understand the explanation. How would I solve this with ...
*February 13, 2015 by Anonymous*

**geometry**

ughh i need help i dnt like proofs we'll here it the instructions write a two column proof the segment addition postulate is useful for this proof also. remember that the transitive && substitution properties are common in proofs this one requires substitution.. given is rs=xy...
*September 24, 2009 by samm*

**Chemistry**

I was wondering if anyone could describe a general Friedel-Crafts alkylation to me. I understand that it involves the substitution of an aromatic ring with an alkyl group using a strong Lewis acid catalyst. But, what types of activating groups are present on the ring? What's ...
*March 1, 2012 by Jenny*

**chemistry**

What will be the fastest reaction if a strong base, such as sodamide, reacts with a secondary alcohol, such as (2S)-butanol? a) deprotonation of the alcohol b) substitution with racemization of stereochemistry c) elimination to form the more substituted alkene d) substitution ...
*March 29, 2013 by michelle*

**Substitution Method-Plz help**

Use the Substitution method to solve the system of equations. x + y = -4 x - y = 2 solve for x in the second equation. x= y+2 Put that in for x in the first equation: x+y=-4 (y+2) + y = -4 solve for y. Then, x= y+2 i don't get it.How did you get that?What does x equal? re read...
*October 17, 2006 by Svetlana*

**Algebra II**

For the following, I believe I have the correct answers: 3 * 6 - 3 * 4 = 18 - 12 Substitution Property because you are substituting 18 for 3 * 6 If s = 3, then s * 2 = 3 * 2 Substitution Property because you are substituting 3 for the s Did I name the correct properties? Thank...
*August 19, 2015 by Mom50*

**organic chemistry**

How can gas chromatography determine what mechanism a reaction underwent? For example, I was to synthesize an alkyl halide using 1-propanol, NaBr, and sulfuric acid. I know its a substitution reaction, but how can gas chromatography tell me whether its SN1 or SN2 substitution?
*April 20, 2009 by needhelpwithchem*

**Alg-Substitution (check plz)**

k well i had to use substitution to find the point of intersection for these 2 equations x-y=10 3x+y=11 i chose to substitute y in the first equation my final answer was (-1/2 , 5) can someone clarify this, and if it's wrong, where'd i make a mistake? In the first equation, y...
*February 22, 2007 by thomas*

**substitution method**

solve using the substitution method 8x -9y= -95 5x+64=y The solution is (___,___)
*July 20, 2010 by upbeat*

**substitution method**

solve using the substitution method 6x+2y=-14 -5x+y=25 The solution is (___,___)
*July 20, 2010 by upbeat*

**substitution method**

solve using the substitution method 8x+6y=8 -9x+y=22 The solution is (___,___)
*July 20, 2010 by upbeat*

**Linear Equations**

Can you please help solve this equation using the substitution method? I have tried and keep getting that X and Y = 7/2, but the answer in the book states no solution, inconsistent system. What am I doing wrong? Please help! Solve the systems of equations by the substitution ...
*March 2, 2010 by Mia*

**Microeconomics**

1. The utility function is given by: U=x+y and the budget line is x+2y=100. Then the price of good x goes up to 4. Find the Hicksian substitution effect, income effect, and total change in demand for good x from the change --- Ok i read the theory but i cant solve the problem ...
*November 28, 2006 by Andrew*

**calculus**

Assuming that: Definite Integral of e^(-x^2) dx over [0,infinity] = sqrt(pi)/2 Solve for Definite Integral of e^(-ax^2) dx over [-infinity,infinity] I don't know how to approach the new "a" term. I can't use u-substitution, integration by parts, partial fractions, or trig ...
*January 14, 2008 by mathstudent*

**Math**

12x+4y= 22 and 3x-8y= -10 What are the coordinates of x and y? Use the Substitution Method. ---and--- -5x+7y= -41 and 7x+y=25 What are the coordinates of x and y? Use the Substitution Method. Please help!!! =DDD
*January 25, 2008 by Catherine*

**chemistry**

carboxylic acid plus alcohol yields ester plus water. It is an organic substitution reaction wot type of reaction is this CH3CO2H + C6H5CH2OH---------------> CH3COOCH2C6H5 + water is it like a substitution or like an addition or wot?
*December 19, 2006 by bobpursley*

**Algebra - solving linear equations w/ substitution**

The question in the book reads: "Suppose you try to solve a system of linear equations using substitution and get this result. How many solutions does each system have?" 1)x=-2 2)y=12 3)6=x 4)-8=-8 5)7=y 6)5=3 I understand #3 and #6, but I do not understand how to know how ...
*March 19, 2007 by Samantha*

**Substitution Method**

Use the Substitution method to solve the system of equations. x + y = -4 x - y = 2 x + y = -4 x - y = 2 In the second equation, x= y+2 Putting that in the first.. (y+2) + y= -4 subtract two from each side, then divide each side by two to get y. Then, put that value of y into ...
*October 16, 2006 by Margie*

**substitution method**

solve by the substitution method 2m+n=9 m-6n=50 the solution is (___,___)
*July 20, 2010 by upbeat*

**MATH**

Useing substitution/elimination method what is the solution set to 2x+y=1 x^2=y+2 a)(-3,7) and (1,-1) b)(3,7) and (-1,-1) c)(-3,-7) and (1,1) d)(3,-7) and (-1,1) I've really no educated guess so PLEASE HELP! You can make an educated guess by substituting the various (x,y) ...
*January 16, 2007 by Anonymous*

**Geometry HELP!!**

I need help with my geometry hw, i need to now wat the properties are for the following statements. 1. If 2x=6, then x=3 2. If 42 degrees + measure of angle 2 = 90 degrees, then measure of angle 2 = 48 degrees 3. If measure of angle D = 40 degrees and measure of E = 90 degrees...
*November 11, 2009 by Anonymous*

**Economic**

A Giffin good is not correctly described by which of the following? A)A Giffin good must be an inferior good. B)A Giffin good must be such that the income effect and the substitution effect move in opposite directions, and the income effect outweighs the substitution effect. C...
*April 11, 2010 by Dina*

**Math-Algebra**

Solve: 3x-2y=10 2x+3y=-2 Graph: Substitution: Elimination: Show Your work! (I can'tfigure out how to graph it and when i used substitution and elimination it came out with two different anwsers. I need help! and i need to be able to show my work!)
*January 17, 2011 by Darryl*

**ECON**

PLEASE CHECK AND CORRECT MY ANSWERS!!!! MRTS = marginal rate of technical substitution RTS = returns to scale MP = marginal product Suppose the production function is Cobb-Douglas and f(x1, x2) = [x1^(1/2)][x2^(3/2)]. (Note: x1 and x2 are variables). a) Select an expression ...
*October 14, 2009 by Anonymous*

**algebra 1**

3) for any factorable trinomial x^2+bx+c, will the absolute value of b sometimes,always, or never be less than the absolute value of c? explain idk 4) give an example of a trinomial that can be factored using the factoring techniques presented. then factor the trinomial. idk 5...
*April 17, 2013 by hi*

**math**

Note: You can get full credit for this problem by just answering the last question correctly. The initial questions are meant as hints towards the final answer and also allow you the opportunity to get partial credit. Consider the definite integral from pi/6 to pi/2 cos(z)/...
*January 25, 2014 by kitor*

**microeconomics**

Fact 1: "The substitution effect(SE) must ALWAYS be negative (i.e. goes in the opposite direction to the change in PRICE). The income effect(IE) can be either positive or negative." Fact 2: "SE and IE can go in the same direction or they can go in opposite directions...
*October 18, 2009 by Victor*

**Algebra help!**

Please help and I would appreciate an explanation as to how you got to the answer. 1.) Solve the system by triangularizing the augmented matrix and using back substitution. 0.09x-0.15y+0.39 -0.18x+0.35y=-0.88 2.) Solve the system by triangularizing the augmented matrix and ...
*March 27, 2013 by Kristen*

**biology**

Make a single base pair substitution mutation in the gene below that results in a protein that is shorter than the protein produce by the original gene. When you are satisfied with your change and its effect, click the "Final Check" button. Note that a "single base pair ...
*November 18, 2013 by juanpro*

**microeconomics**

How the technical rate of substitution and marginal product are related and what is their difference? i only wrote their definitions The technical rate of substitution measures the rate which the firm has to substitute one input for another, for keeping the output stable. It ...
*December 21, 2012 by liza*

**Algebra**

I have a few questions I need help with! 1. Solve the system by triangularizing the augmented matrix and using back substitution. If the system is linearly dependent, give the solution in terms of a parameter. -3x+y-z=-4 6x-2y+2z=8 -12x+4y-4z=-16 2. Solve the system by ...
*March 27, 2013 by Kristen*

**macroeconomics**

(Import Substitution Versus Export Promotion) Explain why domestic producers who supply a good that competes with imports would prefer an import-substitution approach to trade policy rather than an export- promotion approach. Which policy would domestic consumers prefer and why?
*December 21, 2009 by Amber*

**Algebra help!**

1.) Solve the system by triangularizing the augmented matrix and using back substitution. -x-y+z=1 x-y-4z=-7 4x+y+z=6 2.) Perform the indicated row operation, then write the new matrix. -4 4 | 4 9 -6 | 5 -2R1+ R2 ---> R2 3.) Solve the system by triangularizing the augmented...
*March 28, 2013 by Becca*

**Algebra help needed please!!**

I have a few questions I need help with! 1. Solve the system by triangularizing the augmented matrix and using back substitution. If the system is linearly dependent, give the solution in terms of a parameter. -3x+y-z=-4 6x-2y+2z=8 -12x+4y-4z=-16 2. Solve the system by ...
*March 28, 2013 by Kris*

**Bio**

a) Make a single base pair substitution mutation in the gene below that results in a mature mRNA that is shorter than the mature mRNA produced by the original gene. When you are satisfied with your change and its effect, click the "Final Check" button. Note that a "single base...
*May 14, 2013 by Amos Amines*

**Algebra**

Can someone please help solve this? Solve by using addition or substitution or addition. 10x+2y=7 y=-5x+3 the answer my got was x=11/10 y=-2 My teacher said that was wrong. Never mind this post I found out how to solve it. Try substitution. 10 x + 2(-5x +3) = 7 That leads to 6...
*May 9, 2007 by jessica*

**BIOLOGY**

b) Make a single base pair substitution mutation in the gene below that results in a protein that is shorter than the protein produce by the original gene. When you are satisfied with your change and its effect, click the "Final Check" button. Note that a "single base pair ...
*November 17, 2013 by youlifex*

**Math Homework**

Hello! I need help with these math questions, thanks! :) 1.) Solve the system by substitution. 5x + 2y = -17 x = 3y 2.) Solve the system by substitution. x/3 + y = 4/3 -x + 2y = 11 3.) Solve the system by elimination. 2x - 3y = 0 2x + 6y = 3 4.) Solve the system by elimination...
*December 7, 2013 by Beni*

**Geometry**

How do I solve this? Complete the two-column proof. Given : 11x – 6y = –1; x = 8 Prove: 89/6= y 11x – 6y = –1; x = 8 88 – 6y = –1 –6y = –89 y = 89/6 89/6= y • a. Given; b. Symmetric Property of Equality; c. Subtraction Property of Equality; d. Division Property of Equality; e...
*October 9, 2014 by Sandra*

**biology mit**

b) Make a single base pair substitution mutation in the gene below that results in a protein that is shorter than the protein produce by the original gene. When you are satisfied with your change and its effect, click the "Final Check" button. Note that a "single base pair ...
*November 17, 2013 by juanpro*

**Calculus URGENT test tonight**

Integral of: __1__ (sqrt(x)+1)^2 dx The answer is: 2ln abs(1+sqrt(x)) + 2(1+sqrt(X))^-1 +c I have no clue why that is! Please help. I used substitution and made u= sqrt(x)+1 but i don't know what happened along the way! Your first step was a good one. next, let u = sqrt x + 1 ...
*April 20, 2007 by Gabriela*

**algebra**

Requesting help. (I must reckon, that X is a variable, and y is y-intercept) Q: Try to use the substitution method to solve the the linear system y=3x an y=3x-7. What do you notice? A) What happens when you graph it? B) Explain why there is no solution. And... Q: Try to use ...
*October 6, 2008 by Michael*

**Algebra multiple choice! **

I have a few questions I need help with! Please explain if my answer was not right how you got to it. I got 1.) B 2.) A 3.) C 1. Solve the system by triangularizing the augmented matrix and using back substitution. If the system is linearly dependent, give the solution in ...
*March 28, 2013 by Becca*

**substitution method**

y=x-7 2x+y=8
*November 4, 2009 by j.hargrove*

**SUBSTITUTION**

HOW TO SOLVE Y=6X-11 & -2X-3Y=-7
*February 6, 2010 by PRINCESS*

**SUBSTITUTION**

HOW TO SOLVE FOR Y=6-11 & -2X-3Y=-7
*February 6, 2010 by PRINCESS*

**Substitution method**

x=2y y=2x+3 ??
*December 14, 2010 by Ashley*

**math**

substitution 4x + 3y = 3 7x - 9y = 6
*January 13, 2011 by al*

**Substitution Method**

4x+5y=12 2y=6x+8
*July 4, 2011 by Alexis*

**Math - Trig Substitution**

How can I solve the integral of x^3√(9-x^2) dx using trigonometric substitution? ? ∫ x^3√(9-x^2) dx So then I know that x = 3sinθ dx = 3cosθdθ When I substitute, it becomes ∫ (3sinθ)^3 * √(9-(3sinθ)^2) * 3cosθdθ...
*September 8, 2008 by Marissa*

**Math: Equations of Lines**

[b]WHERE DID I GO WRONG?[/b] [b]Question:[/b] Find the intersection of each pair of lines. If they do not meet, determine whether they are parallel and distinct or skew. n) [(x - 3)/4] = [y - 2] = [z - 2] [(x - 2)/-3] = [(y + 1)/2] = [(z - 2)/-1] ---------------- [b]My Attempt...
*March 17, 2008 by Anonymous*

**Calculus**

I have two questions, because I'm preparing for a math test on monday. 1. Use the fundamental theorem of calculus to find the derivative: (d/dt) the integral over [0, cos t] of (3/5-(u^2))du I have a feeling I will be able to find the derivative easily, I'm just having trouble...
*May 9, 2009 by Jennifer*

**macro**

Assume that the utility function of a consumer is given by U = ln c1 + ln c2 The interest rate is given by 5% and the endowments are given by (y1, y2) = (100, 120). (a) Draw the budget constraint. (b) Calculate the consumption and saving in period 1. (c) Draw the indifference ...
*May 19, 2015 by steven*

**Algebra**

How to solve by substitution: 8x - 4y = 16 y = 2x - 4
*January 23, 2008 by Carl*

**algebra**

Solve by substitution: 8x - 4y =16 y=2x -4
*January 23, 2008 by Carl*

**Prealgebra**

Solve by substitution: x+y=9 y=2x
*April 6, 2008 by Jillian*

**Algebra 2**

2x-y=-6 -4x+2y=-9 use substitution
*September 30, 2008 by Keyshawna*

**substitution method**

1. y=x+4 y+3x 2. y=3x-10 y= 2x-5 3.x=-2y+! x=y-5 4.y=5x+5 y=15x-1 5.y=x-3 y=-3x+25 6.y=x-7 2x+y=8
*February 1, 2009 by Asal*

**Substitution Method Algebra**

4x+y=6 y=2x
*March 2, 2009 by LeeLee*

**MATH**

x+y=-4 (x-2)^2+(y+7)^2=13 solve by substitution
*May 12, 2009 by LT*

**math**

solve by substitution: a-1.2b=-3 0.2b+0.6a=12
*September 15, 2009 by anonimous*

**algebra**

solve by substitution, 9x+2y=-64
*October 29, 2009 by sonia*

**algebra**

Solve by substitution: y=x-4 x+y=14
*November 1, 2009 by Sharon*

**algebra**

Sovle by substitution: 2x-3y=9 4x-6y=-12
*November 1, 2009 by Sharon*

**Math**

Solve by substitution: x + 2y =1 8x + 8y =4
*March 14, 2010 by HELEN*

**9th grade**

substitution for 5r-s=5 -4r+5s=17
*April 14, 2010 by Anonymous*

**algebra**

how do you solve 3x-y=5 and =6x+2y=1 by substitution
*June 12, 2010 by Anonymous*

**ALgebra**

use substitution 3x-2y=11 x-y/2=4
*October 25, 2010 by mike*

**algebra**

use substitution x/3-y=3 2x+y=25
*October 25, 2010 by mike*