Friday

November 27, 2015
**Calculus**

Lines tangent to the curve y-1=2x^2+3x pass through the point A(2,-1). Find the x-coordinate(s) of the point(s) of tangency. The answer is 2+2^1/2, 2-2^1/2, I just don't know how to get there. Please help! Thank you!
*Sunday, December 7, 2014 by Ty*

**Pre calculus**

at an archaeological site remains of plant material will found to have 28.9% of the amount of carbon-14 in a living sample. What was the approximate age of the plant material?
*Saturday, December 6, 2014 by crisly*

**calculus**

the length of a rectangular prism is increasing at a rate of 8 cm/s, its width is increasing at a rate of 3 cm/s, and its height is increasing at a rate of 5 cm/s. when the length is 20 cm, width is 10 cm, and height is 15 cm, how fast is the volume of the rectangular prism ...
*Saturday, December 6, 2014 by Dani*

**calculus**

definite integral of (e^(8x))cosh(8x)dx from 0 to 1/16 -I substitued the definition of cosh in, i.e. (e^(8x) + e^(-8x)/2 but i cant get the "e's" to combine and i know the answer is e/32
*Saturday, December 6, 2014 by gregory*

**Pre Calculus**

You have been hired by the Humane Society to construct six 2 by 3 animal cages using 1400 feet of chain fence. Express the length and width using function notation. Include a graph with the area function with explanation of significance. Find the dimensions that maximize the ...
*Friday, December 5, 2014 by Guillermo*

**Calculus**

Find the interval on which f(x)=xe^-x is increasing. I got (1,infinity)..
*Friday, December 5, 2014 by Anonymous*

**Calculus**

On what intervals is the function f(x)=e^e^2 increasing? Concave upward?
*Friday, December 5, 2014 by Anonymous*

**calculus Please Help**

The cost for a toy company to produce x Cosmic Starships is C(x) = 1400 + 6x − 0.01x2. What ￼￼￼￼￼￼￼￼￼￼is the marginal average cost function? Can someone please explain how to do this to I...
*Friday, December 5, 2014 by Erica*

**Calculus**

Differentiate. cos^-1 2x
*Friday, December 5, 2014 by Anonymous*

**Calculus**

Differentiate. cos^3x My answer: -3cos^2x sin^2x
*Friday, December 5, 2014 by Anonymous*

**Calculus**

Find the interval on which f(x)=xe^-x is increasing. I got (1,infinity)..
*Friday, December 5, 2014 by Anonymous*

**Calculus**

If f(x)=the sqrt of 3x,find f'(3). Isn't it 3/2•sqrt of 3?
*Friday, December 5, 2014 by Anonymous*

**Calculus Please Help**

Can you please explain these two questions to me? Suppose the population size of a predator is given by P (x) = 0.006x2 + 0.005x, where x represents the population of its prey. If the population of the prey is 10,000 at the first of January and is reduced to 6,000 by May 1 of ...
*Friday, December 5, 2014 by Eric*

**Calculus**

How do I find the area of the region bounded by the graphs of the given equations? y=x+20; y=x^2
*Friday, December 5, 2014 by Duane*

**Calculus question please explain**

I know the answer to the first one is "e" and the answer to the second one is "a "but I have no idea why please explain how to do these two problems. I am very confused with this method. Thank you! The “Cobb-Douglas” productivity function for a ...
*Friday, December 5, 2014 by Jennifer *

**calculus**

If sec x = -3, 0 < x < pi, find cot x.
*Thursday, December 4, 2014 by Grant*

**pre-calculus**

6cos^2(x)-5cos(x)-6
*Thursday, December 4, 2014 by Ashleigh*

**Calculus**

can you show me the steps to evaluate this indefinite integral. s(e/x^4+pie^2/square root of x
*Thursday, December 4, 2014 by Duane*

**Calculus**

The marginal profit in dollars on Brie cheese sold at a cheese store is given by P'(x)=x(60x^2+30x), where x is the amount of cheese sold in hundreds of pounds. The "profit" is -$50 when cheese is sold. a. Find the profit function. P(x)= b. Find the profit from ...
*Thursday, December 4, 2014 by Duane*

**Calculus**

a particle moves along the x-axis at a velocity of v(t)=1 sqrt(t), t>0. at time t=1 , its position is x=4. find the acceleration and position functions for the particle
*Thursday, December 4, 2014 by Steph*

**Calculus**

A sherman is in a rowboat on a lake and 3 km from shore. He wishes to reach a store 2 km down the (straight) shore. He can row at 5 km/h and run at 13 km/h. To what point down-shore should he row to get to the store as quickly as possible? 8. The cross-section of a tunnel
*Wednesday, December 3, 2014 by Lucy*

**Calculus **

With the following coordinates (16,46) (18,64) (20,60) create three formulas using Y+Ax^2+Bx+C then solve for A,B, and C to form the final equation.
*Wednesday, December 3, 2014 by Hailey*

**CALCULUS - PLEASE HELP!**

It is known that homing pigeons tend to avoid flying over the water in the daytime, perhaps because the downdrafts of air over water make flying difficult. Suppose a homing pigeon is released on an island at point C , which is 3 km directly out in the water from a point B ...
*Tuesday, December 2, 2014 by Mary*

**calculus 2**

Find all points of intersection of the given curves. (Assume 0 ≤ θ ≤ 2π. Order your answers from smallest to largest θ. If an intersection occurs at the pole, enter POLE in the first answer blank.) r = 1 − cos θ, r = 1 + sin θ
*Tuesday, December 2, 2014 by Linda*

**Calculus**

Differentiate. e^cos(x^2+1) Is the answer -2xe^cos(x^2+1) sin(x^2+1)?
*Monday, December 1, 2014 by Anonymous*

**calculus**

Let f'(x)=4x^3-12x^2. (a) find three different functions with derivative equal to f'(x). how are the graphs of the three functions related? the only one that i can figure out is: f(x)=x^4+4x^3+y where y can equal any constant. any help on figuring out the other two ...
*Monday, December 1, 2014 by kailee*

**calculus**

When a ball is thrown vertically upward into the air with a velocity of 79 ft/sec its height, y(t), in feet after t seconds is given by y(t) = 79t − 16t 2 . Find the average velocity of the ball over the interval from 3 to 3 + h seconds, h 6=/= 0. 1. average vel. = &#...
*Monday, December 1, 2014 by Morgan*

**calculus**

I needed help with these FRQ in my APCalc course. Any help or walkthrough would be extremely helpful - thanks in advance. Let f be the function given by f(x)=3ln((x^2)+2)-2x with the domain [-2,4]. (a) Find the coordinate of each relative maximum point and each relative ...
*Monday, December 1, 2014 by emily*

**General Calculus Question**

On a graph what ways can it not be differentiable? I know at cusps it's not differentiable but are there other instances where it is not differentiable?
*Monday, December 1, 2014 by Anonymous*

**Calculus**

Water is being poured into a spherical bowl of radius 4cm at a rate of 2cm3/s. How fast is the water level rising when it is at 2cm?
*Monday, December 1, 2014 by Sam*

**calculus, help!**

Evaluate the definite integral: int_{1}^{e^9} \frac{dx}{x \sqrt{\ln x}} = i gt my answer as 1^(e^9) but it's saying it's wrong
*Monday, December 1, 2014 by Amber *

**Calculus**

consider the function f(x) = (x if x<1 (1/x if x>or equal to 1 Evaluate the definite integral: int_{-2}^{3} f(x)\,dx =
*Monday, December 1, 2014 by Amber *

**Calculus**

Which of the following functions does not have a derivative of zero? A. y=-1/100 B. y=4(pi)^2-9 C. y=sin^2x+cos^2x D. y=cscxtanxcosx E. All do
*Monday, December 1, 2014 by Anonymous*

**Calculus**

Estimate the area under the graph of f(x)= x^2 + 2 x from x=1 to x=5 using 4 approximating rectangles and left endpoints.
*Monday, December 1, 2014 by Kate*

**Calculus...help**

The projected public spending by the British government for the years 2010-2011 (t = 0) through 2014-2015 (t = 4) is 692 billion pounds/year. The projected public revenue for the same period is f(t) = 292.6t + 134.4 / t + 6.9 + 500 billion pounds (0 ge t ge 4). Find the ...
*Monday, December 1, 2014 by sarah*

**calculus**

The number of U.S. citizens 65 and older from 1990 through 2050 is estimated to be growing at the rate of, R(t)=0.063t^2 -0.48t+3.87, (0 less than or = t less than or = 15) million people/decade, where t is measured in decades and t = 0 corresponds to 1900. Show that the ...
*Sunday, November 30, 2014 by mar*

**Differential equations in Calculus...plsssss help?**

Suppose that represents the temperature of a cup of coffee set out in a room, where T is expressed in degrees Fahrenheit and t in minutes. A physical principle known as Newton’s Law of Cooling tells us that dT/dt = -1/15T+5 15T + 5. a) Supposes that T(0) = 105. What does ...
*Sunday, November 30, 2014 by Bridget*

**Calculus**

Find the limit as x approaches 1 5/(x-1)^2 I don't understand how to solve it because there would be a 0 on the denominator.
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

Find dy/dx if x^2+y^2=2xy A. x/(x-y) B. (y+x)/(y-x) C. 1 D. -x/y E. None of these
*Sunday, November 30, 2014 by Anon*

**Calculus with Diffrential Equations: Pleease help?**

Suppose that represents the temperature of a cup of coffee set out in a room, where T is expressed in degrees Fahrenheit and t in minutes. A physical principle known as Newton’s Law of Cooling tells us that dT/dt = -1/15T+5 15T + 5. a) Supposes that T(0) = 105. What does ...
*Sunday, November 30, 2014 by Bridget*

**Calculus**

Suppose that represents the temperature of a cup of coffee set out in a room, where T is expressed in degrees Fahrenheit and t in minutes. A physical principle known as Newton’s Law of Cooling tells us that dT/dt = -1/15T+5 15T + 5. a) Supposes that T(0) = 105. What does ...
*Sunday, November 30, 2014 by Bridget*

**Help with differential eqs problem???? (Calculus)**

Consider the differential equation dy/dt=y-t a) Determine whether the following functions are solutions to the given differential equation. y(t) = t + 1 + 2e^t y(t) = t + 1 y(t) = t + 2 b) When you weigh bananas in a scale at the grocery store, the height h of the bananas is ...
*Sunday, November 30, 2014 by Stacey*

**Calculus**

The slope of the line tangent to the curve xy+(y+1)^2=6 at the point (2, 1) is
*Sunday, November 30, 2014 by James*

**AP Calculus **

For which of these functions f(x) does limit as x approaches negative infinity f(x)=2 A. (x-2)/(3x-5) B. 2x/sqrt(x-2) C. (2x^2-6x+1)/(1+x^2) D. (2x-1)/(x^2+1) E. None of these
*Sunday, November 30, 2014 by Sarah*

**Calculus**

Find limit as x approaches 5 (x^2-3x-10)/(x-5)
*Sunday, November 30, 2014 by Anonymous*

**AP Calculus**

Find the derivative for f(x)=-x^2+x Do I put -x^2 on the denominator? How would I solve it if that's the case?
*Sunday, November 30, 2014 by Sarah*

**Calculus**

Find limit as x approaches -1 (x^2+2x+3)/(x^2+1) A. 0 B. 1 C. Infinity D. DNE E. None of these
*Sunday, November 30, 2014 by Anonymous*

**AP Calculus**

Find f'(x): f(x)=(x^2-3x)/x^2 A. 2x-3/x^2 B. 2x-3/2x C. 1-(3/x) D. 3/x^2 E. None of these I get confused on the simplifying part.
*Sunday, November 30, 2014 by Anon*

**AB Calculus**

I figured out that part "A" is -3/8, but i can't figure out part 2, a or b. please explain and help. thanks. Sand is falling from a rectangular box container whose base measures 40 inches by 20 inches at a constant rate of 300 cubic inches per minute. a) how is ...
*Sunday, November 30, 2014 by Jake*

**AP Calculus**

Find limit as x approaches 1 5/(x-1)^2 A. 0 B. Negative infinity C. 5/4 D. Infinity E. None of these
*Sunday, November 30, 2014 by Anon*

**Calculus**

Find the derivative: f(x)=1/cubed root(3-x^3) A. -1/3(3-x^3)^4/3 B. x^2/(3-x^3)^4/3 C. -x^2/(3-x^3)^2/3 D. -x^2/(3-x^3)^4/3 E. None of these
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

If f(x)=x^2+1 and g(x)=2x-1, find d/dx[f'(g(x))] at x=1 A. 2 B. 6 C. 4 D. 0 E. None of these
*Sunday, November 30, 2014 by Anon*

**AP Calculus**

Find all points on the graph of f(x)=-x^3+3x^2-2 where there is a horizontal tangent line.
*Sunday, November 30, 2014 by Sarah*

**Calculus**

Find the limit as x approaches 0 [(sqrt(x+9))-3]/x A. 0 B. 1 C. Infinity D. 1/3 E. None of these
*Sunday, November 30, 2014 by Anonymous*

**Calculus,Reaction rates**

A man walks across a bridge at the rate of 5 ft/s as a boat passes directly beneath him at 10 ft/s. If the bridge is 10 ft above the boat, how fast are the man and the boat separating 1 second later?
*Sunday, November 30, 2014 by ray*

**AP Calculus**

Let f(7)=0, f'(7)=14, g(7)=1, g'(7)=1/7. Find h'(7) if h(x)=f(x)/g(x)
*Sunday, November 30, 2014 by Sarah*

**Calculus**

Find the derivative of x^2f(x) A. x[xf'(x)+2f(x)] B. 2xf'(x) C. x[xf'(x) +2f'(x)] D. x^2f'(x) E. None of these
*Sunday, November 30, 2014 by Anonymous*

**Calculus,reaction rates**

A car starting at 12:00 noon travels west at a speed of 30 kph. Another car starting from the same point at 2:00 PM travels north at 45 kph. Find how fast the two are separating at 4:00 PM?
*Sunday, November 30, 2014 by @jayr*

**Calculus**

Find an equation of the tangent line to the graph of x^2+3y^2=4 at the point (1,1) A. y+1=-1/3(x+1) B. y-1=-x/3y(x-1) C. x+3y=2 D. y-1=-1/3(x-1) E. None of these
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

Find the equation of the line that passes through (1,3) and is perpendicular to the line 2x+3y+5=0 A. 3x-2y+3=0 B. 2x+3y-11=0 C. 2x+3y-9=0 D. 3x-2y-7=0 E. None of these I got E?
*Sunday, November 30, 2014 by Anonymous*

**Calculus (Cross Section) again**

A half of a pepperoni stick is 10 cm long. Assume that a cross section perpendicular to the axis of the pepperoni at a distance x from the end if a circle of radius rad(3x). What is the volume of the pepperoni
*Sunday, November 30, 2014 by Trinh*

**Calculus (cross section)**

A solid has a base bounded by x^2_y^2=36. Find the volume of the solid if every plane section perpendicular to the diameter is an isosceles triangle whose base is on the circle and whose height is 4 units
*Sunday, November 30, 2014 by Trinh*

**Calculus**

If f(1)=4 and f'(1)=2, find an equation of the tangent line at x=1 A. y=2x+2 B. y=2x-2 C. y=4x-7 D. y=4x-2 E. None of these
*Sunday, November 30, 2014 by Anonymous *

**Calculus**

Find f'(x) if f(x)=sin^3(4x) A. 4cos^3(4x) B. 3sin^2(4x)cos(4x) C. cos^3(4x) D. 12sin^2(4x)cos(4x) E. None of these I got D using the chain rule?
*Sunday, November 30, 2014 by Anonymous *

**Calculus**

Which of the following describes the graph of y=|2x+6|? A. Only continuous B. Only differentiable C. Both A and B D. Not continuous, not differentiable E. Constant
*Sunday, November 30, 2014 by Anon*

**Calculus**

Find d^2y/dx^2 for y=(x+3)/(x-1) A. 0 B. y=-8/(x-1)3 C. y=-4/(x-1)^3 D. y=8/(x-1)^3 E. None of these I got a positive number but am not sure about the denominator in the second derivative.
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

Find dy/dx for y=sin(x+y) A. 0 B. (cos(x+y))/(1-cos(x+y) C. cos(x+y) D. 1 E. None of these I know I'm supposed to use implicit differentiation but I'm not sure how to go about it with sin
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

Find an equation of the tangent line to the graph of f(x)=xsinx when x=0. A. y=0 B. f'(x)=0 C. y=xcosx+sinx D. y=x E. None of these
*Sunday, November 30, 2014 by Anonymous*

**AP calculus**

Find values for x and/or y on the graph of x^2-2y^2+9x+8y-276=0 for which there is a vertical tangent line
*Sunday, November 30, 2014 by DJjazzyjazz*

**Calculus**

For which of these functions f(x) does limit as x approaches negative infinity f(x)=2 A. (x-2)/(3x-5) B. 2x/sqrt(x-2) C. (2x^2-6x+1)/(1+x^2) D. (2x-1)/(x^2+1) E. None of these
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

Find limit as x approaches 5 (x^2-3x-10)/(x-5) A. 2 B. DNE C. 0 D. 7 E. None of these
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

If f(x) = {x^2+3x-1, x<=2 and -3bx+3, x<2 , find the value of b in order for f to be continuous
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

If f(x) = {x^2+3x-1, x<=2 and -3bx+3, x<2 , find the value of b in order for f to be continuous
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

If f(x)=sin(2x), find f"(x) A. 2cos(2x) B. -4sin(2x) C. -2sin(2x) D. -4sinx E. None of these Is it B from using chain rules?
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

Find the derivative for f(x)=-x^2+x Do I put the -x^2 as a denominator? How would I solve it if that's what I'm supposed to do?
*Sunday, November 30, 2014 by Anonymous*

**Calculus **

Find limit as x approaches -1 (x^2+2x+3)/(x^2+1) A. 0 B. 1 C. Infinity D. DNE E. None of these
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

Find limit as x approaches 1 5/(x-1)^2 A. 0 B. Negative infinity C. 5/4 D. Infinity If I use limit as h approaches 0 f(x+h)-f(x)/h , will I get an x in the answer?
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

Find dy/dx if x^2+y^2=2xy A. x/(x-y) B. (y+x)/(y-x) C. 1 D. -x/y E. None of these Do I equal it to 0 and use implicit rule?
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

Find f'(x) for f(x)=(2x^2+5)^7 A. 7(4x)^6 B. 7(4x)^7 C. 28x(2x^2+5)^7 D. 7(2x^2+5)^6 E. None of these Would it be none of these because of the 4x in the chain rule?
*Sunday, November 30, 2014 by Anonymous*

**Calculus**

Determine the limit as x approaches 1 f(x) if f(x)={3-x, x does not equal 1 and 1, x=1 A. 2 B. 1 C. 3/2 D. DNE E. None of these
*Sunday, November 30, 2014 by Anonymous*

**math calculus**

convert these symmetric equations to parametric form: line 1:(x-1)/k = (y-2)/2 = (z+1)/k-1 and line 2: (x+3)/-2 = (z)/1, y=-1
*Saturday, November 29, 2014 by Sarah*

**math calculus**

For the function: f(x)= 2+x-x^2/ (x-1)^2 ; f'(x)= x-5/(x-1)^3 ; f''(x)=2x-14/(x-1)^4 a)find vertical and horizontal asymptotes. Examine vertical asymptote on either side of discontinuity. b)find any local extrema c)find points of inflection
*Saturday, November 29, 2014 by Sarah*

**Pre-Calculus**

You have been hired by the Humane Society to construct six animal cages using 1400 feet of chain fence. Express the length and width using function notation. Include a graph with the area function with explanation of significance. Find the dimensions that maximize the total ...
*Friday, November 28, 2014 by Guadalupe*

**Calculus I**

An open box with square base is to be constructed. The material for the base costs $10 per square foot. The material for the sides costs $1 per square foot. the box must have an area of 100 square feet. Find the dimensions of the box that minimize cost. What I have so far: A...
*Friday, November 28, 2014 by Brian*

**Calculus**

What is the smallest possible slope for a tangent to y=x^3 - 3x^2 + 5x? (I'm unsure how to approach this problem, if you know how to solve it, please explain step by step. THANK YOU!!!)
*Friday, November 28, 2014 by Suzy*

**Calculus**

An aquarium is to be constructed to hold 2160 in3. The base is to made of slate and the sides of glass. If slate costs 5 times as much as the glass per sq in, find the dimensions that will minimize the cost of constructing the aquarium. I started going about this problem by ...
*Friday, November 28, 2014 by Patrick*

**calculus**

Baseball Star Bryan is standing at the top of the Sears Tower in Chicago and decides to throw a baseball up with a velocity of 5 m/s. The Sears Tower is 442 meters tall and gravity exerts a constant acceleration of -9.8 m/s/s. Ignore ball mass and wind resistance. a.) Find ...
*Friday, November 28, 2014 by Jay*

**Calculus**

solve the differential equation dy / dx = 11x^2y^2 with the condition that y(0) = 4 The solution to the equation is y =
*Wednesday, November 26, 2014 by Anonymous*

**Brief Calculus**

Find the area of the indicated region. We suggest you graph the curves to check whether one is above the other or whether they cross, and that you use technology to check your answer. (Round your answer to four significant digits.) Enclosed by y = e^x, y = 2x + 1, x = −2...
*Tuesday, November 25, 2014 by Matt*

**Calculus**

5) Evaluate the definite integral. On the integral from 1 to e^7 ∫dx/x(1+lnx)
*Tuesday, November 25, 2014 by Hailey*

**Calculus**

2) If f(x)=∫t^2dt not he integral from 4 to x^3 then f′(x)=?
*Tuesday, November 25, 2014 by Hailey*

**Calculus**

20) Evaluate the definite integral. On the integral from e to e^3 ∫dx/xl(nx)^(1/2)
*Tuesday, November 25, 2014 by Hailey*

**Calculus**

The sales of Universal Instruments in the first t years of its operation are approximated by the function S(t) = t 0.96t2 + 25 where S(t) is measured in millions of dollars. What were Universal's average yearly sales over its first 5 years of operation?
*Tuesday, November 25, 2014 by Kathleen*

**calculus**

A) Determine the vector equation of the plane that contains the following two lines: l1: vector r= [4,-3,5] + t[2,0,3], tER l2: vector r= [4,-3,5] + s[5,1,-1], sER b)Determine the corresponding Cartesian equation.
*Monday, November 24, 2014 by Sarah*

**math calculus**

if i,j,k are the standard unit basic vectors, in 3 space, determine the value of k dot(j-3k)+(i-4k) dot (i-4k)-8 |i cross -k| (Simplify without using components)
*Monday, November 24, 2014 by Tina*

**calculus**

(i know i've asked so many questions. i just want to make sure my answers are right for this homework! hopefully it isn't too annoying for you :) ) Find the derivative of the given function. y=(tan^-1)√(3x) A. (1)/(√(1-3x)) B. (1)/(6√(3x(1+3x))) C. (3...
*Monday, November 24, 2014 by kailey*

**calculus**

Me again. One last question! Again, just needed my answer verified with any explanation or walk-through. The position of a particle moving along a coordinate line is s=√(3+6t) with s in meters and t in seconds. find the particle's acceleration at t=1 second. a. 1 m/...
*Monday, November 24, 2014 by kailey*

**Calculus**

What does y'' mean in calculus? Is there a word for it? Also is there a word for f'(x)? Thanks.
*Monday, November 24, 2014 by anonymous*

**calculus**

hello! i just needed help to verify or falsify my answer and any explanation as to why would be extremely helpful! thanks ahead of time. y=(x^2)-6x+10 a. at x=3 b. at x=0 c. at x=1 d. at x=-3 my answer was D. thanks again!
*Monday, November 24, 2014 by kailey*

**calculus**

hello! i just needed help to verify or falsify my answer and any explanation as to why would be extremely helpful! thanks ahead of time. y=(x^2)-6x+10 a. at x=3 b. at x=0 c. at x=1 d. at x=-3 my answer was D. thanks again!
*Monday, November 24, 2014 by kailey*