Sunday

July 24, 2016
**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*

**Calculus using the first derivative**

Y=e^x differentiate using the first principle
*Sunday, September 6, 2015 by Edward*

**Pre-Calculus HELP!**

change the polar equation r=5/1+cos(theta) to rectangular form. How do I do this? Thank you! :)
*Sunday, September 6, 2015 by Ellie*

**calculus**

what is the range for the function j(x)=5+sqrt of 2-x
*Saturday, September 5, 2015 by anon*

**PRE CALCULUS**

1.) The cash flow per share for the Timerland Co. was $0.18 in 1995 and $4.04 in 2003. Write a liner equation that gives the cash flow per share in terms of the year. Let t=5 represent 1995. Then predict the cash flows for the years 2008 and 2010. 5.) The University of ...
*Friday, September 4, 2015 by Emma*

**calculus**

a particle starts from rest and moves along a straight line with an acceleration equal to 24-15√t where distance and time are measured in terms of feet and seconds respectively. with what acceleration will the particle return to the starting point?
*Friday, September 4, 2015 by justin*

**calculus**

If the driver of a car wishes to increase his speed from 20 mph to 50 mph while traveling a distance of 528 ft., what constant acceleration should he maintain?
*Friday, September 4, 2015 by justine*

**Pre Calculus **

In exercise 100, you are given the dollar value of a product in 2005 and the rate at which the value of the product is expected to change during the next 5 years. Use this Info. to write a linear equation that gives the dollar value V of the product in terms of the year t. (...
*Thursday, September 3, 2015 by Emma*

**Pre-Calculus**

Write a linear equation to fit the description. The line with a slope of zero containing the y-intercept of x/3 + y/9 = 1 I'm not sure what to do here. Can someone please help me?
*Thursday, September 3, 2015 by Yani*

**Calculus (limits)**

The question is to "state the value of each quantity, if it exists." We are given a piecewise function that is graphed, and no equation. What does it mean when we're asked to find f(2)?
*Thursday, September 3, 2015 by Kelly*

**calculus**

the equation y+y"=0 is the differential equation of? a.)sine function b.)sinusoidal c.)cosine function d.) a and c e.) abc
*Thursday, September 3, 2015 by .do*

**calculus**

determine the diameter of closed cylindrical tank in meters if the volume is 11.3m^3 to get min. surface area.
*Wednesday, September 2, 2015 by .do*

**calculus**

determine the diameter of closed cylindrical tank in meters if the volume is 11.3m^3 to get min. surface area
*Wednesday, September 2, 2015 by .do*

**calculus**

find the largest cylinder w/ height h that can be inscribed in a cone w/ height H
*Wednesday, September 2, 2015 by dope*

**calculus**

Find the area bounded by the curve y=1/2+2, the x-axis, and the lines x=1 and x=4. a.7 1/2 b.10 2/3 c.16 d.28 1/2
*Wednesday, September 2, 2015 by tammy*

**Pre-Calculus**

1) j(x)=-2/3x what is j(x)'s y-intercept? answer: (0,0) 2) k(x)=4 what is k(x)'s slope? answer: 0 3) g(x)=2x-5 what are the root(s) of g(x)? 4) the slope of line p if p is perpendicular to line f are the answers i provided correct? and please help me on 3 and 4
*Tuesday, September 1, 2015 by Sam*

**Pre-Calculus **

focus at (-2,0) directrix the line x=2
*Tuesday, September 1, 2015 by anonymous *

**Pre-Calculus**

Write an equation to fit the description. 0° Celsius = 32° Fahrenheit. 100°C = 212°F. (Let x = degrees Celsius and y=degrees Fahrenheit.) y=9/5x+32 Is this correct?
*Monday, August 31, 2015 by Lucy*

**Calculus **

A 6 feet tall man walks away from a streetlight that is 15 feet high at a rate of 5 ft/s. Express the length 's' of his shadow as a function of time. What I have so far: I set up a triangle and used similar triangles to create a ratio (6/s) = (s/d+s) s = (6d + 30/15s) ...
*Monday, August 31, 2015 by Rosie*

**Calculus**

Differentiate y=[(8x-x^6)/(x^3)]^(-4/5) My answer: [4x^3(16+3x^5)]/5 • fifth root of [(8x-x^6)/(x^3)] ^9
*Sunday, August 30, 2015 by Anonymous*

**Calculus**

Differentiate e^cos (x^2+1). My answer: -2xe^cos(x^2 +1) • sin(x^2+1)
*Sunday, August 30, 2015 by Anonymous*

**Calculus**

Find the equation of the tangent line to f(x)=sec x - 2 cos x at (pi/3, 1).
*Sunday, August 30, 2015 by Anonymous*

**Calculus**

Differentiate. f(x)=(cos x)/x I got to here: (-x sin x - cos x)/x^2
*Sunday, August 30, 2015 by Anonymous*

**math calculus**

Find the half-life (in hours) of a radioactive substance that is reduced by 30 percent in 40 hours.
*Sunday, August 30, 2015 by Urgent help*

**math calculus**

In the year 2005, a picture supposedly painted by a famous artist some time after 1815 but before 1865 contains 95 percent of its carbon-14 (half-life 5730 years). Approximately how old is the painting? In years
*Sunday, August 30, 2015 by Urgent help*

**Calculus**

Differentiate. f(x)=(cos x)/x I got to here: (-x sin x - cos x)/x^2 Find the equation of the tangent line to f(x)=sec x - 2 cos x at (pi/3, 1). Is the slope 3 times sqrt of 3? Equation is y=3 times sqrt of 3x - pi times sqrt of 3 +1??
*Saturday, August 29, 2015 by Anonymous*

**Calculus**

Find the equation of the tangent line to f(x)=x sec x at (pi/4, pi •sqrt of 2 all over 4). I got to here, but did not know what to do next: slope: (pi/4)(sqrt of 2 over 2) + (sqrt of 2 over 2) everything over 1/2=.......
*Saturday, August 29, 2015 by Anonymous*

**Calculus**

Find the derivative. d/dx[sqrt of x (x^3 +1)] My answer in its most simplified form: (7x^3 + 1)/ 2 • sqrt of x
*Saturday, August 29, 2015 by Anonymous*

**calculus**

R is the first quadrant region enclosed by the x-axis, the curve y = 2x + b, and the line x = b, where b > 0. Find the value of b so that the area of the region R is 288 square units.
*Saturday, August 29, 2015 by Anonymous*

**calculus**

The base of a solid is bounded by the curve y= sort (x+2) ,the x-axis and the line x = 1. The cross sections, taken perpendicular to the x-axis, are squares. Find the volume of the solid.
*Saturday, August 29, 2015 by Anonymous*

**Math (Pre-calculus)**

The Fiedler family has up to $130,000 to invest. They decide that they want to have at least $40,000 invested in stable bonds yielding 5.5% and that no more than $60,000 should be invested in more volatile bonds yielding 11%. How much should they invest in each type of bond to...
*Saturday, August 29, 2015 by ELVIA*

**pre-calculus**

Rewrite each equation into slope intercept or special case form. 1) 4x+3=8x 2) 9y-(7+3y)=0 I have no idea how to do these two. Can someone please help me? 3)x/2+y/7=1 My answer is y=-7x+14. Is this correct?
*Saturday, August 29, 2015 by d*

**Math (Pre-calculus)**

An artist is creating a mosaic that cannot be larger than the space allotted which is 4 feet tall and 6 feet wide. The mosaic must be at least 3 feet tall and 5 feet wide. The tiles in the mosaic have words written on them and the artist ants the words to all be horizontal in ...
*Saturday, August 29, 2015 by ELVIA*

**calculus**

Find the domain for the particular solution to the differential equation dx/dy=1/2x, with initial condition y(1) = 1.
*Saturday, August 29, 2015 by Anonymous*

**integral calculus**

integrate. (1):sin2xcos3x (2):5(cos3x)^2
*Saturday, August 29, 2015 by edward*

**calculus**

A snowball is melting at the rate of 2 inches per hour. How fast is the surface area of the snowball changing at the instant the snowball has a radius of 3 inches i tried (d/dt) = 4pir^2 (dr/dt) its multiple choice and -72pi isnt there so im just trying to figure this out
*Friday, August 28, 2015 by Thomas*

**Calculus**

Let f be a function defined for all real numbers. Which of the following statements must be true about f? Which might be true? Which must be false? Justify your answers. (a) lim of f(x) as x approaches a = f(a) (b) If the lim of f(x)/x as x approaches 0 = 2, then f(0)=0. (c) ...
*Friday, August 28, 2015 by Anonymous*

**pre-calculus**

h(t)=15t + 1200 is a function that models the motion of a mountain climber. h(t) is his height above sea level at time t in minutes. 1a) the coefficient on t is 15. what does it tell you about the motion of the mountain climber? 1b) what does it tell you about the graph of h(t...
*Thursday, August 27, 2015 by d*

**calculus**

a colony of bacteria living on a petri dish under optimal conditions doubles in size every ten minutes. At noon on a certain day, the Petri dish completely covered with bacteria. At what times (to the nearest hour, minute and second) was the percentage of the plate covered by ...
*Thursday, August 27, 2015 by john*

**Calculus 1**

simplify the expression. cos(2 tan^-1 x)
*Thursday, August 27, 2015 by TayB*

**Calculus 1**

Find the exact value of each expression. (a) cot^-1(sqrt(3))
*Thursday, August 27, 2015 by TayB*

**Calculus 1**

Find the exact value of each expression. (a) tan(sec^−1 5) (b) sin(2sin^-1(5/13))
*Thursday, August 27, 2015 by TayB*

**AP Calculus**

Find each of the limits without a calculator. Use the limits as an aide to sketch the graph of f(x)= (x-2)/(|x|-2) for-10<_x<_10 and -6<_y<_6. Be sure to clearly indicate any asymptotes, holes or other important characteristics. lim x->∞ f(x)
*Wednesday, August 26, 2015 by Ana*

**Calculus**

True or false. 1. If f(x) has a vertical asymptote at x=a, then the limit of f(x) as x --> a from the left is negative infinite and the limit of f(x) as x--> a from the right is positive infinite. I think this is true. Take for instance, a rational function. the two ...
*Wednesday, August 26, 2015 by Anonymous*

**Calculus**

The equation of a circle, C, is x^2 + y^2 + 6x - 8y +9=0. Find the center of C and find the radius of C. Show that the C touches the x-axis. Find the equation of the circle which is a reflection of C in the y-axis
*Wednesday, August 26, 2015 by Sabrina*

**Calculus **

Derivatives - chain rule An airplane, flying horizontally at an altitude of 1 mile, passes directly over an observer. If the constant speed of the airplane is 400 miles per hour, how fast is its distance from the observer increasing 45 seconds later? Hint: note that in 45 ...
*Tuesday, August 25, 2015 by Ribie*

**Calculus **

Derivatives - chain rule An airplane, flying horizontally at an altitude of 1 mile, passes directly over an observer. If the constant speed of the airplane is 400 miles per hour, how fast is its distance from the observer increasing 45 seconds later? Hint: note that in 45 ...
*Tuesday, August 25, 2015 by Ribie*

**Calculus 1**

Use a graph to estimate the values of x such that e^x > 1,000,000,000
*Monday, August 24, 2015 by TayB*

**calculus**

find the two numbers whose sum is 10, if the product of one by the cube of other is a maximum.
*Monday, August 24, 2015 by jen *

**Calculus **

If 2 < or = to f(x) < or = to x^2 + 2 for all x, find the limit of f(x) as it approaches zero.
*Sunday, August 23, 2015 by Anonymous*

**Calculus **

F(x)=(2x-1)/ (|x| -3) Rewrite f(x) as a piecewise function. Then find the limit as it approaches positive infinity and negative infinity.
*Sunday, August 23, 2015 by Anonymous*

**Differential calculus**

A gutter with trapezoidal cross section is to be made from a long sheet of tin 8 in wide by turning up one third of its width on each side , what width a cross the top that will give a maximum capacity
*Sunday, August 23, 2015 by Grace*

**calculus**

y=2^nx differentiate with respect to x using the first principle
*Sunday, August 23, 2015 by edward*

**Calculus **

If 2 < or = to f(x) < or = to x^2 + 2 for all x, find the limit of f(x) as it approaches zero.
*Sunday, August 23, 2015 by Anonymous*

**Calculus **

F(x)=(2x-1)/ (|x| -3) Rewrite f(x) as a piecewise function. Then find the limit as it approaches positive infinity and negative infinity.
*Sunday, August 23, 2015 by Anonymous*

**calculus: don't even no where to start from need help plz**

(1)find dy/dx of y if y=tan^(-1)1/x^2 (2) if y=3z^2.z^2 find dy/dz (3) if y=x^x show that dy/dx=x|n(x+1).. thanks
*Sunday, August 23, 2015 by edward*

**Calculus **

Find the limit as it approaches zero. ( f( x + change in x) - f(x) )/ change in x given f(x)=2x-5. ( change in x = triangle x)
*Sunday, August 23, 2015 by Anonymous*

**Calculus **

Graph the function f(x)= x sin( 1/x) and the equations y=|x| and y=-|x| in the same viewing window on your calculator. Then use the squeeze therom to find the limit of f(x) as it approaches zero. I graphed the function and equations, but I am confused on how to find the limit ...
*Sunday, August 23, 2015 by Anonymous*

**Calculus**

What would the limit be for the following problems? lim (square root (x+3)) x--> 1 I thought it would be 1.4 lim (1/x) x--> 7 I thought it would be 0 or .1 but neither of those show to be correct. Thank you!
*Saturday, August 22, 2015 by Serena*

**Calculus 1**

A variable star is one whose brightness alternately increases and decreases. For one such star, the time between periods of maximum brightness is 4.7 days, the average brightness (or magnitude) of the star is 5.3, and its brightness varies by ±0.35 magnitude. Find a ...
*Saturday, August 22, 2015 by TayB*

**Calculus**

A line rotates in a horizontal plane according to the equation Y = 2t^3- 6t, where Y is the angular position of the rotating line, in radians, and t is the time, in seconds. Determine the angular acceleration when t = 2 sec.
*Saturday, August 22, 2015 by Linda*