Wednesday

August 24, 2016
**Calculus**

We are finding critical numbers f(x)= 8x^3+x^2+8x f'(x)=24x^2+2x+8 -> 2(12x^2+x+4) I'm honestly stuck. All I can tell is that I need to set my f'(x)=0, but I am lost there too. Quadratic form. equates to (-1±i√191)/24 I believe. That is as far as I ...
*Sunday, October 4, 2015 by Justin*

**Calculus**

We are finding critical numbers f(x)= 8x^3+x^2+8x f'(x)=24x^2+2x+8 -> 2(12x^2+x+4) I'm honestly stuck. All I can tell is that I need to set my f'(x)=0, but I am lost there too. Quadratic form. equates to (-1±i√191)/24 I believe. That is as far as I ...
*Sunday, October 4, 2015 by Justin*

**calculus**

If f(x) = 5ex cos x, find f '(x) and f ''(x).
*Sunday, October 4, 2015 by jam*

**calculus i need help also**

If y=2x^2-21x^2+60x+6 what is the value of x? dx^2/dy^2=0
*Saturday, October 3, 2015 by collins*

**calculus need help**

use the first principle to obtain the differencial coefficient y=1/(2x-1)
*Saturday, October 3, 2015 by collins*

**Calculus**

The revenue for a sale of x books at $70 each is given by R(x)=70x. The commission for a revenue of x dollars is given by C(x)=.20x. Express the commission as a function of the number of books sold.
*Saturday, October 3, 2015 by Suzanne*

**Calculus 1**

Find y' if y=ln(9x^2+7y^2).
*Friday, October 2, 2015 by TayB*

**Calculus 1**

Find the equation of the tangent line to the curve y = (9 ln x)/x at the points (1, 0) and (e, 9/e).
*Friday, October 2, 2015 by TayB*

**Pre-calculus**

Find the inverse function of f(x) = 4 - 8/x^2, where x>0 What I think is because there is a restriction to domain (x>0), the function is invertible since sqrt(x) will always result in +-x. Am I right?
*Thursday, October 1, 2015 by Lid*

**AP Calculus**

a norman window is constructed by adjoining a semicircle to the top of an ordinary rectangular window. find the dimensions of a norman window of maximum area if the total perimeter is 72 units. Base value is 21.
*Thursday, October 1, 2015 by Tom*

**Calculus**

Show that u(x, t) = f(x−ct)+g(x+ct), where c is a constant and f and g have continuous second derivatives, is a solution of the wave equation in one dimension, ie (∂t)^2 u = c^2 ∂x^2 u. Note that this solution to the wave equation consists of two functions ...
*Wednesday, September 30, 2015 by Margo*

**Multivariable calculus**

Find dy/dx x=te^t y=t+sint
*Wednesday, September 30, 2015 by Anonymous*

**math,(integral calculus)**

Integrate with respect to x:4x^2.dx
*Wednesday, September 30, 2015 by I-learn*

**Calculus**

The equation of motion of a particle is s = t3 − 12t, where s is in meters and t is in seconds. For the velocity function, I got v(t)=3t^2-12 and for acceleration, a(t)=6t. The final question is: Find the acceleration when the velocity is 0. How do I do that?
*Tuesday, September 29, 2015 by Kelly*

**Calculus 1**

The curve with the equation y^2=5x^4-x^2 is called a kampyle of Eudoxus. Find an equation of the tangent line to this curve at the point (-1,2).
*Tuesday, September 29, 2015 by TayB*

**Calculus 1**

Use implicit differentiation to find an equation of the tangent line to the curve at the given point. x^2/3 +y^2/3 =4 (-3sqrt(3),1) (astroid)
*Tuesday, September 29, 2015 by TayB*

**Calculus 1**

Use implicit differentiation to find an equation of the tangent line to the curve at the given point. x^2+2xy-y^2+x=6 , (2,4) (hyperbola)
*Tuesday, September 29, 2015 by TayB*

**Calculus**

Find the antiderivatives. 1. f(x)= x sin (x^2) 2. f(x)= x sin x
*Tuesday, September 29, 2015 by Anonymous*

**calculus**

1. what trig function has an amplitue of 1 and negative values for angles between π/2 and π? 2. what trig function never crosses the x-axis and has a value of 2 at π/6? are these correct? 3. what trig function has a period of π and is undefined for -π/...
*Monday, September 28, 2015 by anon*

**Calculus**

Find y" by implicit differentiation. x^3+y^3 = 1 (x^3)'+(y^3)' = (1)' 3x^2+3y^2(y') = 0 3y^2(y') = -3x^2 y' = -3x^2/3y^2 y' = -x^2/y^2 y" = [(y^2)(-x^2)'-(-x^2)(y^2)']/y^4 y" = [(y^2)(-2x)-(-x^2)(2y)]/y^4 y" = [(-2xy^2...
*Sunday, September 27, 2015 by Justin*

**Calculus**

Let u=f(r) and r=|x|=((x1)^2 +···|(xn)^2)^1/2. Show that ∑ (∂u/∂xj)^2 = (f′(r))^2 Please help! it's an assignment due tomorrow
*Sunday, September 27, 2015 by Sarah*

**Calculus**

Let u=f(r) and r=|x|=(x1^2 +···|xn^2)^1/2. Show that ∑ 1 to n (∂u/∂xj)^2 = (f′(r))^2
*Sunday, September 27, 2015 by Martha*

**Physics**

The figure below represents part of the performance data of a car owned by a proud physics student. (The horizontal axis is marked in increments of 1 s and the vertical axis is marked in increments of 10 m/s.) f (a) Calculate the total distance traveled by computing the area ...
*Sunday, September 27, 2015 by Kaleem*

**Calculus**

Consider the line through the points (3,2,5) and (1,1,1). Consider the plane A that is perpendicular to this line, and passing through the point (-1,0,2). Consider the plane B that passes through the points (1,-1,0), (0,2,0), and (0,5,2). Consider the intersection of plane A ...
*Sunday, September 27, 2015 by Alexa*

**Calculus**

limit (x^2+y^2)/(x+y)^2 as (x,y)->(0,0) I don't know how to prove it doesn't exist. Please help!
*Sunday, September 27, 2015 by Margo*

**calculus**

domain of -9/2+t^2 and 1-4t/2+t
*Saturday, September 26, 2015 by Anonymous*

**Calculus**

Let f(x)=1/x. Compute the difference quotient for f(x) at x=1 with h=0.3 I know that the formula for difference quotient is (f(x+h)-f(x))/h, but I am not sure how I am supposed to plug this in. I have tried a few ways but webworks says that the answer is wrong every time.
*Saturday, September 26, 2015 by :(*

**differential calculus**

differentiate g(t)=3/sqrt(t)
*Saturday, September 26, 2015 by Anonymous*

**Calculus**

You are expecting a tax refund of $4,000 in 4 weeks. A tax preparer offers you an "interest-free" loan of $4,000 for a fee of $50 to be repaid by your refund check when it arrives in 4 weeks. Thinking of the fee as interest, what simple interest rate would you be ...
*Saturday, September 26, 2015 by Anonymous*

**Calculus**

Just got through with derivatives, power rule, and chain rule. I am supposed to find the first and second derivatives of the function. y = 4x/√x+1 and y = cos^2(x) y' = [(x+1)^(1/2)(4)]-[(4x)(1/2(x+1)^(-1/2))(1)] y' = [4(x+1)^(1/2)-4x]/[2(x+1)^(1/2)(x+1)] ...
*Saturday, September 26, 2015 by Justin*

**Calculus**

The Norman window illustrated below has a semicircular section on top of a rectangle. The radius of the semicircle is x. The long side of the rectangle is three times the radius of the semicircle. a)Express the total area of the window, A, as a function of x. b) Express the ...
*Friday, September 25, 2015 by Ellie*

**Calculus**

We just learned derivatives and now on the Chain Rule. y = r/[(sqrt)(r(sqrd)+1)] y' = [[(sqrt)(r(sqrd)+1)(r)'] - [(r)(sqrt)(r(sqrd)+1)']] / [(sqrt)(r(sqrd)+1)](sqrd) y' = (sqrt)(r(sqrd)+1) - r[1/2(r(sqrd)+1)(raised to -1/2)](2r) My final answer is -3r/[2(sqrt)(...
*Friday, September 25, 2015 by Justin*

**calculus**

Find the point on the curve y = x^3 which is nearest the point (4, 0).
*Friday, September 25, 2015 by Anonymous*

**calculus**

Find the point on the curve y =2/3 〖√(18-x^2 )〗 (first quadrant) where a tangent line may be drawn so that the area of the triangle formed by the tangent line and the coordinate axes is a minimum.
*Friday, September 25, 2015 by Anonymous*

**calculus**

A rectangular field is to be fenced, one side of which is the edge of a straight river. It is given that the material for the two opposite side costs Php 3.00 per meter and the material for the side opposite the river costs Php 6.00 per meter. If an amount of Php 600.00 is ...
*Friday, September 25, 2015 by Anonymous*

**calculus**

A manufacturer of a certain brand of appliance estimates that he can sell 5000 units a year at Php 900.00 each and that he can sell 1500 units more per year for each Php 100.00 decrease in price? What price per unit will give the greatest returns?
*Friday, September 25, 2015 by Anonymous*

**Calculus 1**

The curve y = |x|/(sqrt(5- x^2)) is called a bullet-nose curve. Find an equation of the tangent line to this curve at the point (2, 2)
*Friday, September 25, 2015 by TayB*

**Pre Calculus**

The doubling period of a baterial population is 10 minutes. At time t=80 minutes, the baterial population was 50000 1What was the initial population at time t=0 2Find the size of the baterial population after 4 hours
*Thursday, September 24, 2015 by Marina*

**Calculus**

Find all solutions of the equation correct to three decimal places. (ex: 0.617 or -1.764) x^3=3x-3
*Thursday, September 24, 2015 by Alisha*

**Calculus**

Which of the following is not a solution to the following equation? x^3-5x^2+4 = 0 x = 0 x = 4.83 x = -0.83 x = 1
*Thursday, September 24, 2015 by Alisha*

**calculus**

with respect to x;4^2.dx
*Thursday, September 24, 2015 by loveth*

**Calculus **

Maclaurian' series example "f(x)=tanx" give me answer
*Thursday, September 24, 2015 by Swapnil *

**Calculus 1**

Find the derivative of the function. y=(e^3u -e^-3u)/(e^3u+e^-3u)
*Thursday, September 24, 2015 by TayB*

**pre-calculus**

Almonds cost fiver per pound and cashews cost nine per pound. How many pounds of almonds should be mixed with the cashews to make 10 pounds of a mix that sells for eight dollars per pound?
*Wednesday, September 23, 2015 by mary*

**calculus **

simplify the given expression using factors 1. 5(x^2+4)^4(2x)(x-2)^4+(x^2+4)^5(4)(x-2)^3 2. (x^2+3)^(-1/3)-2/3x^2(x^2+3)^(-4/3) 3. 2x(x+6)^4-x^2(4)(x+6)^3/(x+6)^8 4. (7-3x)^1/2+3/2x(7-3x)^(-1/2)/7-3x
*Wednesday, September 23, 2015 by Anonymous*

**calculus **

dont get it write intervals for the function sin(x)/1-cos (x) is continuous on.
*Wednesday, September 23, 2015 by Anonymous*

**Calculus**

How do you simplify vectors? 1)AB + BC + CD 2) BC - FE - BA + DE - DC Calculus - Steve, Tuesday, September 22, 2015 at 11:39pm AB+BC = AC so, AB+BC+CD = AD BC-DC = BC+CD = BD See if you can use that idea to rearrange +/- terms so the ends line up in order Calculus - Anonymous...
*Tuesday, September 22, 2015 by Anonymous*

**Calculus**

How do you simplify vectors? 1)AB + BC + CD 2) BC - FE - BA + DE - DC
*Tuesday, September 22, 2015 by Anonymous*

**Calculus**

Can you please explain to me what are the qualifications for a function to be continuous? Please explain your response in easy to understand wording. thank you in advanced!
*Tuesday, September 22, 2015 by Catera *

**Calculus **

What does it mean when the limit of f(c) doesn't exist?
*Tuesday, September 22, 2015 by Catera *

**Calculus 3! ASAP please**

1.A given line is described by the system of equations x=2t+7; y=-3t+4; z=5-t; find the equation of a line parallel to the given line and which contains the point (1,1,0). 2.Let a=<0,6,2> and b=<0,2,4>, then the component of a parallel to b is given by? - the ...
*Tuesday, September 22, 2015 by Sally*

**Calculus 3 **

1. An object moves along a straight track from the point (1,−2,1) to the point (0,−7,5). The only force acting on it is a constant F=2i−3j−5k newtons. Find the work done if the distance is measured in meters. 2. A wrench 0.5 meters long lies along the ...
*Tuesday, September 22, 2015 by jagga*

**Calculus 1**

Differentiate. f(x)=5sqrt(x)sinx
*Tuesday, September 22, 2015 by TayB*

**Calculus**

Differentiate each function with respect to x: F(x)=x/(x+1)^1/2
*Monday, September 21, 2015 by Sm*

**Pre-Calculus**

how to make a xy table for the following greatest integer equation when using -1,-2,0,1,2 to plug into x f(x)=2[x], g(x)=[2x], f(x)=-[[x]], and g(x)=[[-x]]
*Monday, September 21, 2015 by s*

**Pre-Calculus**

Why does sin 30° = 150° (or sin π/6 = sin 5π/6)? Refer to both the unit circle and the graph of the sine curve.
*Monday, September 21, 2015 by A*

**calculus**

10. A military jet flies horizontally with a velocity of 450 m/s and 20,000 m above the ground. When the jet is straight above an artillery gun a shell is fired. Assuming the shell hits the jet. a. Calculate the horizontal component of the initial velocity of the shell. b. ...
*Sunday, September 20, 2015 by Sue*

**calculus**

Please answer. An airplane at an altitude of 3000m, flying horizontally at 300km/hr, passes directly over an observer. Find the rate at which it is approaching the observer when it is 5000m away.
*Sunday, September 20, 2015 by joecel*

**Pre-Calculus**

how do i find the vertical asymptote of x−1 / x(x-2) so far i got x-1 / x^2-2x
*Sunday, September 20, 2015 by Devin *

**pre calculus**

The minute hand and the hour hand of a clock have lengths inches and inches, respectively. Determine the distance between the tips of the hands at 10:00 in terms of and m h.
*Sunday, September 20, 2015 by jim*

**Calculus**

If the function f is defined by f(x)=0 if x is rational f(x)=1 if x is irrational prove that lim x-->0 f(x) does not exist. Can someone help me answer this question step by step so I would know how to prove a question like this next time? Thank you.
*Saturday, September 19, 2015 by Anonymous*

**Calculus**

I don't know limits fairly well. The problem is prove the limit using definition 6, lim x -> -3, 1 / (x+3)^4 = infinity. The books definition for definition 6 is, let f be a function defined on some open interval that contains a, except possibly at a itself, then lim x...
*Saturday, September 19, 2015 by Anonymous*

**Differentitate:calculus**

Differentitate:X^2.sinx/(x+1)(x^2-1)......???
*Friday, September 18, 2015 by Edward*

**Calculus**

Oil is leaking from an oil tanker, and an expanding circle of oil is spreading on the ocean. The radius, r, of the circle measured in inches is modeled by the function r(s)=3 sqrt root s , where s is time in seconds. The area of the spill when seconds is s=5 seconds.
*Friday, September 18, 2015 by Caitlin*

**Calculus**

lim as x approaches pi/4 of (1-cotx)/(cosx-sinx)
*Thursday, September 17, 2015 by Carin*

**Pre-Calculus **

Parabolas; find Vertex, focus, directrix? 1) (y+1)^2 = -4(x-2)
*Wednesday, September 16, 2015 by anonymous *

**calculus**

lim h → 0 (−2 + h)2 − 4 h
*Tuesday, September 15, 2015 by Anonymous*

**Calculus**

I have done one part of this question. I am, however, unsure as to how to set up the graph. Can someone help me? 1. Use a graph to find a number N such that |(6x^2+5x-3)| | |------------- -3 | < 0.2 whenever x>N |(2x^2-1)| | y=2.8 and y=3.2 My issue is how to find the x...
*Tuesday, September 15, 2015 by Anonymous*

**Calculus**

May someone answer this question for me? Thank you! I appreciate it. a.) Use the definition of continuity and the properties of limits to show that the function is continuous on the given interval. f(x)=(2x+3)/(x-2), (2, ∞)
*Tuesday, September 15, 2015 by Anonymous*

**Calculus**

I know the derivative of x is 1, but I'm having a hard time proving it with the limit definition of the derivative. I have... Lim delta x ->0 (x+ delta x)-(x)/delta x = 0 But I know the answer is 1. I don't understand what I am doing wrong
*Monday, September 14, 2015 by K*

**Calculus**

Find the limit as x approaches infinity. sqrt(81x^2 + x)− 9x. I've worked this two different ways and have gotten 0 and 1/9, neither of which is the right answer according to the homework system??
*Monday, September 14, 2015 by kelly*

**Calculus**

If a rock is thrown upward on the planet Mars with a velocity of 19 m/s, its height (in meters) after t seconds is given by H = 19t − 1.86t^2. When will the rock hit the surface?
*Monday, September 14, 2015 by kelly*

**Calculus 1**

Find the derivative of f'(x) of f(x)=4sqrt(x) using limits
*Monday, September 14, 2015 by TayB*

**Calculus 1**

Find the slope of the tangent line and the equation of the tangent line to f(x)=x^2-x at x=3
*Monday, September 14, 2015 by TayB*

**Calculus 1**

Find the horizontal and vertical asymptotes of (3x^2-48)/(x^2-3x+10)
*Monday, September 14, 2015 by TayB*

** Calculus**

A funnel is constructed by removing a sector form a circular metal sheet with 7 inch radius. Determine the maximum volume of the funnel constructed in this way if the small amount of volume lost at the tip of the funnel is neglected.
*Monday, September 14, 2015 by Kingsly*

**pre calculus**

A ship’s sonar detects a submarine 880 feet below a point on the ocean’s surface 1450 ft dead ahead of the ship. To the nearest degree, find the angle x.
*Monday, September 14, 2015 by devante*

**Calculus**

How can I show that the function F (x)= the integral from 2x to 5x of 1/ t dt is constant on the interval (0, +∞).
*Sunday, September 13, 2015 by Anonymous*

**calculus**

A rock is thrown upward with a speed of 48 feet per second from the edge of a cliff 400 feet above the ground. What is the speed of the rock when it hits the ground? Use acceleration due to gravity as –32 feet per second squared and approximate your answer to 3 decimal ...
*Sunday, September 13, 2015 by Anonymous*

**Pre-calculus- URGENT**

Convert the rectangular coordinate (-8,i (square root of 3) into polar coordinates. How do I do this?? I tried every way I knew of to convert the y coordinate (i (square root of three)) to polar form, but it didn't work. I think that the polar form of the x coordinate is ...
*Sunday, September 13, 2015 by Ellie*

**Calculus**

Let f(x) be the function f(x)={x2−c for x<4, {3x+4c for x≥4. Find the value of c that makes the function continuous.
*Saturday, September 12, 2015 by Lou*

**Pre-calculus**

write the complex number -5 in polar form. I don't get how to do this because arctan of b/a would be 5/0 which is a fraction with no solution. Also, is a zero? Sorry if I'm being confusing! Thank you!
*Saturday, September 12, 2015 by Ellie*

**Calculus 1**

A particle moves along a straight line with equation of motion s = f(t), where s is measured in meters and t in seconds. Find the velocity and speed when t = 5. (Round your answers to two decimal places.) f(t) = t^−1 − t *We havent learned derivative yet but we ...
*Saturday, September 12, 2015 by TayB*

**ap calculus**

((1/-2-h)-1)/h
*Friday, September 11, 2015 by alex*

**CALCULUS**

How do I determine whether the function is even, odd, or neither. How do I describe the symmetry? ex 1) f(t)= t&2 +2t -3
*Friday, September 11, 2015 by SARA*

**CALCULUS**

20.) How do I find the zeros of the function algebraically? ex1) f(x)= x^3 -4x^2 -9x +36 ex3) f(x)= 3 +(5/x) ex7) f(x) = (2x^2-9)/ (3-x)
*Friday, September 11, 2015 by SARA*

**Calculus**

solve for x: 6x=ex+1
*Friday, September 11, 2015 by Anonymous*

**calculus ab **

Use a graphing utility to graph the function and visually estimate the linits h(x)= -x^2 + 4x
*Friday, September 11, 2015 by chris*

**calculus**

hey guys, quick question (-8 +- sqrt -20)/-6 what does this equal
*Friday, September 11, 2015 by Karlie*

**Calculus**

If a ball is thrown into the air with a velocity of 34 ft/s, its height (in feet) after t seconds is given by y = 34t − 16t^2. Find the velocity when t = 1.
*Thursday, September 10, 2015 by kelly*

**Pre-Calculus**

A rectangular window is topped with a semicircle. The height of the rectangular part is 1 more than 3 times its width, w meters. Which function represents the total area, A, of the window in terms of the width?
*Thursday, September 10, 2015 by Caitlin*

**Calculus**

Verify the following identities, cos 3x = 4 cos^(3) x - 3 cos x
*Thursday, September 10, 2015 by Ribie*

**Calculus 1**

Find the requested derivative using limits a. 𝑓′(-4)if f(x)=sqrt(1-2x) b. 𝑓′(a)if f(x)=(2x+1)/(x+3) c. 𝑓′(x) if f(x)=x^-2
*Thursday, September 10, 2015 by TayB*

**Calculus 1**

Find the instantaneous velocity, using limits, for the given value of t of an object moving according the given equation. a. s(t)=t^2–8t+18 ; t=3 b. 𝑠(𝑡)=1/t^2 ; t=1
*Thursday, September 10, 2015 by TayB*

**Calculus and Vectors**

In triangle RST, RS=4, RT=7, and ST=5. Determine the measures of the angles to the nearest degree. I solved correctly for T's angle of 34 degrees. Once I try using the sine law to solve for angle S, I keep getting 78 degrees, when it's supposed to be 102 degrees. I ...
*Wednesday, September 9, 2015 by Chuck*

**CALCULUS -HELP!**

How do you find all real values of x such that f(x)=0? Example 1: f(x)=15-3x Example 2: f(x)= (12-x^2)/5 Example 3: f(X)= x^3 -x
*Wednesday, September 9, 2015 by JAKE*

**Calculus**

If a ball is thrown into the air with a velocity of 40 ft/s, its height in feet t seconds later is given by y = 40t − 16t^2. Find the average velocity for the time period beginning when t = 2 and lasting for each of the following. 1) 0.5 seconds.
*Wednesday, September 9, 2015 by kelly*

**calculus**

D(x)=x^2+2x C={(x,y)|y=4x-5} 1) D(C(x)) f(x)=1+3 sqrt of x+2 2) f(f(x))
*Tuesday, September 8, 2015 by anon*

**calculus**

What is the general soln of dy/dx=9(x^2)(y) and particular soln of dy/dx=3x^2(e^-y)
*Tuesday, September 8, 2015 by jhun*

**calculus**

derivative of y=ln(2x-1)
*Monday, September 7, 2015 by herher*