Friday

May 29, 2015

May 29, 2015

** Calculus**

Does the series (cos(k/3))^2/2^(k/3)+1 from k=1 to infinity converge?
*Sunday, March 29, 2015 at 7:29pm*

**Calculus**

Th integral of tan(3x)dx
*Sunday, March 29, 2015 at 7:18pm*

**Calculus 1**

If two resistors with resistances R1 and R2 are connected in parallel, as in the figure below, then the total resistance R, measured in ohms (Ω), is given by 1/R= 1/R1+ 1/R2. If R1 and R2 are increasing at rates of 0.3 Ω/s and 0.2 Ω/s, respectively, how fast is ...
*Sunday, March 29, 2015 at 7:15pm*

**Calculus**

Simplify using basic simplification. y=x^(1-x)
*Sunday, March 29, 2015 at 6:53pm*

**Calculus**

Simplify using basic simplification. f(x)=ln[(sqrt(x^2+1))/(x(2x^3-1)^2)]
*Sunday, March 29, 2015 at 6:45pm*

**Calculus**

Find the equation of the tangent line when x=2 for the functin f(x)=5^(x/2)
*Sunday, March 29, 2015 at 6:28pm*

**Calculus 2 (Series - Convergent or Divergent?)**

Can someone show me a step by step process and explanation how to solve this problem? 1) Consider the following series. (∞ on top of summation symbol) (k = 1 under the summation symbol) ∑ k(k+15)/(k+13)^2 Determine whether the series is convergent or divergent. If ...
*Sunday, March 29, 2015 at 6:12pm*

**Calculus 2**

I need help in solving an initial-value problem and a few series problems (Especially on #45 & #46). I don't really understand how to do the series problems...majority of the time. An explanation would be great as well. Thank you for your time. #20) Solve the initial-value...
*Sunday, March 29, 2015 at 5:52pm*

**Calculus 2 - Series**

I am so confused on how to do series problems...especially these. How can you tell the pattern and determining the formula for them? Can someone please help? 26) Write the first five terms of the sequence {an} whose nth term is given. an = (n + 3)/(2n − 1) a1 = ? a2 = ? ...
*Sunday, March 29, 2015 at 4:31pm*

**Calculus 2 (Differentiate & Decay Problem)**

I have two problems I need help on, can someone show and explain step by step how to do the problems? For #1, how would you differentiate and solve the inital-value problem? For #2, I don't understand what I am doing wrong with the problem..I am sure it is a decay problem...
*Sunday, March 29, 2015 at 3:00pm*

**Calculus**

The area of a circular oil slick is increasing at a constant rate of 2 square miles per day. How fast is the radius increasing when the area is 4(pi) square miles (approximately 12.57 square miles)? So far I have that the area increases at the rate of x+(2mi^2/d) but I don'...
*Sunday, March 29, 2015 at 1:57pm*

**Differential Calculus**

Hi pls help me i dunno what to do show me complete solution please please Thank you. a piece of wire 10ft. long is cut into two pieces , one piece is bent into the shape of a circle and the other into the shape of a square. How should the wire be cut so that: a.)The combined ...
*Sunday, March 29, 2015 at 9:05am*

**integral calculus **

(x^4+6x^3-x^2+2)dx need help
*Sunday, March 29, 2015 at 4:49am*

**integral Calculus **

ʃ (x4 + 6x3 – x2 + 2)dx I really need it for practicing this subject...please please help
*Sunday, March 29, 2015 at 4:46am*

**Calculus **

1. Prove that, among all rectangles with fixed perimeter p, where p > 0, the largest in area is a square. 2. A 2 × 3 array of six congruent rectangular pigpens (that all look the same from above) will be in the overall shape of a rectangle R. We may use 100 feet of ...
*Friday, March 27, 2015 at 11:41am*

**Pre-Calculus**

Solve 0 = 3x^2 + 5x -1 by completing the square. Express your answer as exact roots. 3(x^2 + 5/3 + 25/36) = -1 (x+ 5/6)^2 = 37/36 sq root( x + 5/6)^2 = sq root (37/36) x + 5/6 = +- sq root 37/6 x = -5/6 +- square root 37 /6 <--- (Sorry for the work being so messy! It'd ...
*Thursday, March 26, 2015 at 9:40pm*

**calculus**

A particle moves on a line so that its position at time t seconds is p(t)=3t3 meters to the right of the origin. Find the time c in the interval (4,8) for which the velocity of the particle at time c is equal to the average velocity on the interval [4,8].
*Thursday, March 26, 2015 at 6:51pm*

**Calculus 2 (Differential Equation)**

How would you solve the following problem explicitly? Sqrt(1-y^2) dx - sqrt(1-x^2) dy I separated the x and y terms and got: Integral of 1/sqrt(1-x^2) dx = Integral of 1/sqrt(1-y^2) dy I was wondering how would you take the anti-derivative of each function. I believe we are ...
*Thursday, March 26, 2015 at 3:40am*

**Calculus **

Find the elasticity of the demand function: pq = 42 p=$2 My professor went through this lesson really fast and I would appreciate anyone's help in explaining it. Thank You
*Wednesday, March 25, 2015 at 10:10pm*

**Calculus **

A manufacture has been selling 1300 television sets a week at $420 each. A market survey indicates that for each $16 rebate offered to a buyer, the number of sets sold will increase by 160 per week. a) Find the price p(x) of each television as a function of x, where x is the ...
*Wednesday, March 25, 2015 at 4:32pm*

**Calculus**

A model for the food-price index (the price of a representative "basket" of foods) between 1984 and 1994 is given by the function I(t)=0.00009045t5+0.001438t4−0.06561t3+0.4598t2−.6270t+99.33 Where t is measured in years since midyear 1984, so 0&#...
*Wednesday, March 25, 2015 at 4:29pm*

**Calculus**

The manager of a large apartment complex knows from experience that 80 units will be occupied if the rent is 460 dollars per month. A market survey suggests that, on the average, one additional unit will remain vacant for each 10 dollar increase in rent. Similarly, one ...
*Wednesday, March 25, 2015 at 4:27pm*

**calculus**

Find the intervals on the x-axis on which the function f(x) is increasing and those which it is decreasing, where f(x) = (x)/(x^2+1) I differentiated and got f'(x)=(x^2+1) -(x)(2x) all over (x^2+1)^2 But I don't know what to do now...
*Wednesday, March 25, 2015 at 2:51pm*

**Elasticity Demand Calculus **

Find the elasticity of the demand function: pq = 42 p=$2 My professor went through this lesson really fast and I would appreciate anyone's help in explaining it. Thank You
*Wednesday, March 25, 2015 at 11:50am*

**Pre-Calculus**

Solve. Express your answer as exact roots. (s+6)^2 = 3/4 Sq root (s+6)^2 = +-sq root 3/4 (s+6) = sq root 3/ 2 s = -6 +- sq root 3 ----------------- 2 (The answer according to the textbook is (-12 +- sq root 3)/2. What error have I made?) Thank you
*Wednesday, March 25, 2015 at 8:56am*

**Calculus**

Santr 109 (a fictitious substance) decays by about 6% every day. How much of a 84 pound sample remains after: (a) 7 days (b) 3 weeks (b) 48 days
*Tuesday, March 24, 2015 at 5:27pm*

**calculus**

A cattle rancher wants to enclose a rectangular area and then divide it into six pens with fencing parallel to one side of the rectangle (see the figure below). There are 540 feet of fencing available to complete the job. What is the largest possible total area of the six pens?
*Monday, March 23, 2015 at 10:39pm*

**Calculus**

Let f(x)=5x2+5x−12. Answer the following questions.Find the average slope of the function f on the interval [−1,1].Verify the Mean Value Theorem by finding a number c in (−1,1) such that f′(c)=m¯¯¯.
*Monday, March 23, 2015 at 8:45pm*

**Calculus**

The circumference of a sphere was measured to be 76.000 cm with a possible error of 0.50000 cm. Use linear approximation to estimate the maximum error in the calculated surface area.Estimate the relative error in the calculated surface area.
*Monday, March 23, 2015 at 7:03pm*

**Calculus**

A street light is at the top of a 15 ft tall pole. A woman 6 ft tall walks away from the pole with a speed of 5 ft/sec along a straight path. How fast is the tip of her shadow moving when she is 50 ft from the base of the pole?
*Monday, March 23, 2015 at 6:51pm*

**Calculus**

Water is leaking out of an inverted conical tank at a rate of 0.0142 m3/min. At the same time water is being pumped into the tank at a constant rate. The tank has height 13 meters and the diameter at the top is 3.5 meters. If the water level is rising at a rate of 0.17 m/min ...
*Monday, March 23, 2015 at 6:29pm*

**Calculus**

A spherical balloon is inflated so that its volume is increasing at the rate of 3.2 ft3/min. How rapidly is the diameter of the balloon increasing when the diameter is 1.2 feet?
*Monday, March 23, 2015 at 5:47pm*

**Calculus **

The half-life of Kryponite-123 is 40 years. Suppose we have a 700-mg sample. Find the decay k, and the expected amount of Kryptonite left after 30 years. I need help setting this problem up.
*Monday, March 23, 2015 at 6:38am*

**Calculus **

a bottle of water with temperature 70 F is placed in a refrigerator with an internal temperature of 34 F. After 30 minutes, the temperature of the water has decreased to 52 F a)Give the cooling constant k(6th decimal place), and find an expression for the temperature of the ...
*Monday, March 23, 2015 at 5:51am*

**Calculus **

the population of deer in a certain area of cabarrus county grows proportional to itself. the population of deer in 2000 was found to be 45, and by 2008 the population had grown to 65. Find the growth constant k(rounded to 6 decimal places), and the expected deer population in...
*Monday, March 23, 2015 at 4:13am*

**Calculus Linearizations**

Use this observation and the linear approximation to estimate (15.9)^1/2 I know the answer is 3.9875, I just need someone to explain the steps so I can do problems similar to this one.
*Sunday, March 22, 2015 at 7:01pm*

**related rates calculus 1 **

gravel is being dumped from a conveyor belt at a rate of 15 ft^3/hr and its coarseness is such that it forms a pile in the shape of an inverted right cone whose height is three times its base radius. How fast is the height of the pile increasing when the pile has a height of 10ft
*Sunday, March 22, 2015 at 3:55am*

**Pre-Calculus**

Rewrite each quadratic equation in the form ax^2+bx+c=0. Then,use technology to solve each by graphing. ROund you answers to the nearest hundredth, where necessary. a) 3x^2+30 = -19x Answer: 3x^2+19x+30 Roots: x = -3 b) 6x^2= 25x-24 Answer: -6x^2+25x-24=0 Roots: x = 1.5 c) -33...
*Saturday, March 21, 2015 at 9:33pm*

**Calculus**

suppose that a tumor on a person's body is spherical in shape. if the radius of the tumor is 0.5cm the radius is increasing at the rate of 0.001cm per day. what is the rate of increasing volume of that tumor at that time?
*Saturday, March 21, 2015 at 9:22pm*

**Calculus 1**

If two resistors with resistances R1 and R2 are connected in parallel, as in the figure below, then the total resistance R, measured in ohms (Ω), is given by 1/R= 1/R1+ 1/R2. If R1 and R2 are increasing at rates of 0.3 Ω/s and 0.2 Ω/s, respectively, how fast is ...
*Saturday, March 21, 2015 at 1:23pm*

**Calculus 1**

Water is leaking out of an inverted conical tank at a rate of 12,000 cm3/min at the same time that water is being pumped into the tank at a constant rate. The tank has height 6 m and the diameter at the top is 4 m. If the water level is rising at a rate of 20 cm/min when the ...
*Saturday, March 21, 2015 at 1:01pm*

**Calculus 1**

Gravel is being dumped from a conveyor belt at a rate of 20 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. How fast is the height of the pile increasing when the pile is 7 ft high?
*Saturday, March 21, 2015 at 1:01pm*

**Calculus**

Let f(x)=−x^4−8^x3+5^x+2. Find the open intervals on which f is concave up (down). Then determine the x-coordinates of all inflection points of f. 1. f is concave up on the intervals 2. f is concave down on the intervals 3. The inflection points occur at x =
*Friday, March 20, 2015 at 10:13pm*

**Calculus **

Find constants a and b in the function f(x)=(ax^b)ln(x) such that f(1/5)=1 and the function has a local minimum at x=1/5.
*Friday, March 20, 2015 at 9:55pm*

**Calculus **

Find constants a and b in the function f(x)=axbln(x) such that f(15)=1 and the function has a local minimum at x=15.
*Friday, March 20, 2015 at 9:54pm*

**pre-calculus**

Use the rational root theorem with polynomial division if needed to find all the zeroes of: P(x)=2x^4-3x^3+3x^2+5x-3.
*Friday, March 20, 2015 at 1:52am*

**Calculus AB: Area Between Curves**

Hello! I'm having trouble understanding how I'm supposed to work out this problem. Any help would be appreciated! Find the area of the region bounded by the curve y = f(x) = x3 – 4x + 1 and the tangent line to the curve y = f(x) at (–1,4).
*Wednesday, March 18, 2015 at 1:57pm*

**Pre-Calculus**

Determine a quadratic function with this set of characteristics. x-intercepts of 2 and 7 and maximum value of 25 ( How would I find the x-coordinate for the vertex?) (Thank you!)
*Tuesday, March 17, 2015 at 11:49pm*

**Calculus**

Find the area of the shaded region below. x=(y^2)-2 x=e^y y=1 y=-1 I was doing a horizontal split so I had the integral from -1 to 1 (y^2-2)-e^y dy and had the answer -5.683... and it's wrong. What am I doing wrong?
*Tuesday, March 17, 2015 at 8:28pm*

**Calculus**

1.) Consider the graphs x+5y=17 and x+7=y^2 where a=7 b=2 c=57 f(x) = ? g(x) = ? I have solved for a,b, and c but I can't figure out f(x) and g(x) For f(x) I thought it was (17-x)/5 but it's not the correct answer. For g(x) I thought it was the sqrt(x+7) but it's ...
*Tuesday, March 17, 2015 at 8:25pm*

**Calculus **

Snacks will be provided in a box with a lid (made by removing squares from each corner of a rectangular piece of card and then folding up the sides) link to image imageshack com /a/img661/6094/fZUQXg.jpg You have a piece of cardboard that is 40cm by 40 cm – what ...
*Tuesday, March 17, 2015 at 4:07pm*

**Calculus **

The ride has 100 metres of fencing to make a rectangular enclosure as shown. link for the image imageshack com /a/img909/2881/WTnncK.jpg It will use existing walls for two sides of the enclosure, and leave an opening of 2 metres for a gate. a Show that the area of the ...
*Tuesday, March 17, 2015 at 4:03pm*

**CALCULUS**

If the local linear approximation of f(x) = 3sin x + e3x at x = 2 is used to find the approximation for f(1.9), then the % error of this approximation is
*Tuesday, March 17, 2015 at 3:33pm*

**Integral Calculus**

Find Mx, My, and (x, y) for the lamina of uniform density ρ bounded by y=1/2x ,y>0 x=2
*Tuesday, March 17, 2015 at 11:00am*

**Calculus**

Compute dy/dx using the chain rule. y = (u/4) + (4/u) u = (x - x^7) dy/dx =
*Tuesday, March 17, 2015 at 7:13am*

**Pre-Calculus**

1. A projectile is fired straight up from a height of 6 feet. Its height (h) in feet after t seconds is given by h = 6 + 192t -16t^2. Answer: h = -16t^2 + 192t + 6 h = -16( t^2 -12t +36) + 6 +576 h = -16 (t-6)^2 +582 The maximum height will be 582 feet. 2. The path of a ...
*Monday, March 16, 2015 at 11:56pm*

**calculus trigonometric substitution**

∫ dx/ (x^2+9)^2 dx set x = 3tan u dx = 3 sec^2 u du I = 3 sec^2 u du / ( 9 tan^2 u + 9)^2 = 3 sec^2 u du / ( 81 ( tan^2 u + 1)^2 = sec^2 u du / ( 27 ( sec^2 u )^2 = du / ( 27 sec^2 u = 2 cos^2 u du / 54 = ( 1 + cos 2u) du / 54 = ( u + sin 2u / 2) / 54 = ( arctan x/3 + ...
*Monday, March 16, 2015 at 8:10pm*

**calculus**

find a projectile fired with an initial velocity of 128 feet per second at an angle of 26 degrees
*Monday, March 16, 2015 at 3:53pm*

**calculus**

a 50 m long chain hangs vertically from a cylinder attached to a winch. assume there is no friction in the system and that the chain has a density of 5 kg/m. how much work is required to wind the entire chain onto the cylinder using the winch
*Monday, March 16, 2015 at 11:28am*

**Calculus**

Determine the slope of the tangent to the function f(x)=5e^x - 2e^(2x) at the point with x-coordinate x=1
*Monday, March 16, 2015 at 12:48am*

**Calculus 2 Trigonometric Substitution**

I'm working this problem: ∫ [1-tan^2 (x)] / [sec^2 (x)] dx ∫(1/secx)-[(sin^2x/cos^2x)/(1/cosx) ∫cosx-sinx(sinx/cosx) ∫cosx-∫sin^2(x)/cosx sinx-∫(1-cos^2(x))/cosx sinx-∫(1/cosx)-cosx sinx-∫secx-∫cosx sinx-sinx-&#...
*Sunday, March 15, 2015 at 8:45pm*

**Calculus**

For how many values of x will the tangent lines to y=4sinx and y=x^2/2 be parallel? A. 0 B. 1 C. 3 D. 4 E. Infinite Thanks.
*Sunday, March 15, 2015 at 8:27pm*

**Calculus check**

A function f(x) is continuous for all x and has a local minimum at (1,8). Which must be true? A. f'(1)=0 B. f' exists at x=1 C. The graph is concave up at x=1 D. f'(x) is less than 0 if x is less than 1, f'(x) is greater than 0 if x is greater than 1 E. f'...
*Sunday, March 15, 2015 at 8:24pm*

**Please check my calculus**

A conical tank has a height that is always 3 times its radius. If water is leaving the tank at the rate of 50 cubic feet per minute, how fast if the water level falling in feet per minute when the water is 3 feet high? Volume of a cone is V=1/3(pi)r^2h A. 1.000 B. 5.305 C. 15...
*Sunday, March 15, 2015 at 7:43pm*

**calculus check**

If siny=cosx, then find dy/dx at the point (pi/2, pi) A. -1 B. 0 C. 1 D. pi/2 E. None of these I got C
*Sunday, March 15, 2015 at 7:27pm*

**calculus **

1.) Find the derivative of ((x + 3)/e^x) ^ (Log e X) 2.) T/F (log e X)' = (log e |x|)' 3.) T/F (Log e 7x)' = (log e x)' 4.) Find the derivative of e^(log e 7x)
*Sunday, March 15, 2015 at 7:07pm*

**Calculus check**

Let f(x) be a polynomial function such that f(3)=3, f'(3)=0 and f"(3)=-3. What is the point (3,3) on the graph y=f(x)? A. Relative maximum B. Relative minimum C. Intercept D. Inflection point E. None of these I got C
*Sunday, March 15, 2015 at 5:59pm*

**Please check my calculus**

If x^2+xy-y=2, find dy/dx My answer: (2x+y)/(1-x)
*Sunday, March 15, 2015 at 5:08pm*

**Calculus check**

Given f(x)=x^4(2x^2-15). On what interval(s) is the graph of f concave upwards? A. (0, sqrt(3)) B. (-sqrt(3), 0) C. (-sqrt(3), 0) and (0, sqrt(3)) D. (-sqrt(3), sqrt(3)) E. (Negative infinity, -sqrt(3)) and (sqrt(3), infinity) I got E
*Sunday, March 15, 2015 at 5:05pm*

**calculus**

The graph of the function y=x^5-x^2+sinx has a point of inflection at x= a. 0.324 b. 0.499 c. 0.506 d. 0.611 e. 0.704 Thanks.
*Sunday, March 15, 2015 at 4:55pm*

**Calculus**

For f(x)=x^2/3(x^2-4) on [-2,2] the "c" value that satisfies the Rolle's Theorem is A. 0 B. 2 C. +or-2 D. There is no value for c because f(0) does not exist E. There is no value for c because f(x) is not differentiable on (-2,2)
*Sunday, March 15, 2015 at 4:50pm*

**Calculus check**

An equation of the line tangent to y=sinx+2cosx at (pi/2, 1) is A. 2x-y=pi-1 B. 2x+y=pi+1 C. 2x-2y=2-pi D. 4x+2y=2-pi I got A
*Sunday, March 15, 2015 at 4:16pm*

**Calculus check**

The smallest slope of f(x)=6x^2-x^3 for 0 is less than or equal to x is less than or equal to 6 occurs at x= A. 0 B. 2 C. 3 D. 4 E. 6 I got E
*Sunday, March 15, 2015 at 3:49pm*

**Calculus**

Let f be a function such that the limit as h approaches 0 [(f(5+h)-f(5))/h]=4. Which of the following must be true? I. f(5)=4 II. f'(5)=4 III. f is continuous at x=5 A. I only B. II only C. III only D. I and II only E. II and III only
*Sunday, March 15, 2015 at 3:47pm*

**Calculus check**

The limit as x approaches 1 (x^3-1)/(x^2-1) is I got 3/2
*Sunday, March 15, 2015 at 3:03pm*

**calculus**

What is the limit, as x approaches 1, of (sqrt(x) - 1)/(x - 1)? I need to show work, but I know the answer is 3/2, because I confirmed with a TI-89.
*Sunday, March 15, 2015 at 2:49pm*

**Calculus**

If f'(x)=sinx and f(pi)=3, then f(x)= A. Cosx+4 B. Cosx+3 C. -cosx+2 D. -cosx-2 E. -cosx+4
*Sunday, March 15, 2015 at 2:31pm*

**Please check my Calculus**

f(x)=x^n , where n is a positive integer greater or equal to 2. The graph of f(x) will have an inflection point when n is A. Even B. Odd C. Divisible by 3 D. For all values E. For no values I got B.
*Sunday, March 15, 2015 at 2:06pm*

**Calculus check**

Find the equation of the line tangent to y=tan2x at x=pi/8 A. y-1=sqrt(2)(x-pi/8) B. y-1=1/2(x-pi/8) C. y-1=1/4(x-pi/8) D. y-1=2(x-pi/8) E. y-1=4(x-pi/8) I got A
*Sunday, March 15, 2015 at 11:28am*

**Calculus**

If f(x) is a continuous function with f"(x)=-5x^2(2x-1)^2(3x+1)^3 , find the set of values for x for which f(x) has an inflection point. A. {0,-1/3,1/2} B. {-1/3,1/2} C. {-1/3} D. {1/2} E. No inflection points
*Sunday, March 15, 2015 at 11:26am*

**Calculus**

The integral of sqrt(x)(sqrt(x)+1) dx A. 2(x^3/2+x)+c B. x^2/2+x+c C. 1/2(sqrt(x)+1)^2+c D. x^2/2+2x^3/2/3+c E. x+2sqrt(x)+c
*Sunday, March 15, 2015 at 11:13am*

**Calculus**

Given the function f(x)= sqrtx a) Let M= f´´(50) and N=f''(49). Argue on that f´´(x) lies between M og N if x =]49,50[ (Tip: show that f´´(x) is increasing function, that is look at f´´´(x)). b) Use the numbers from...
*Sunday, March 15, 2015 at 10:48am*

**Calculus**

If y=3x-7, x is greater than 0, what is the minimum product of x^2y? A. -5.646 B. 0 C. 1.556 D. 2.813 E. 4.841
*Sunday, March 15, 2015 at 6:19am*

**Calculus**

If the limit as x approaches infinity (6x^2/200-4x-kx^2)=1/2, then k= A. 3 B. -3 C. 12 D. -12 E. -3
*Sunday, March 15, 2015 at 6:16am*

**Calculus**

A conical tank has a height that is always 3 times its radius. If water is leaving the tank at the rate of 50 cubic feet per minute, how fast if the water level falling in feet per minute when the water is 3 feet high? Volume of a cone is V=1/3(pi)r^2h A. 1.000 B. 5.305 C. 15....
*Sunday, March 15, 2015 at 12:35am*

**Calculus check**

Given f(x)=4+3/x find all values of c in the interval (1,3) that satisfy the mean value theorem. A. 2 B. Sqrt(2) C. Sqrt(3) D. +or- sqrt(3) E. MVT doesn't apply I got C
*Saturday, March 14, 2015 at 11:32pm*

**Calculus**

For how many values of x will the tangent lines to y=4sinx and y=x^2/2 be parallel? A. 0 B. 1 C. 3 D. 4 E. Infinite
*Saturday, March 14, 2015 at 11:30pm*

**Calculus**

if f'(x)=2(3x+5)^4 , then the fifth derivative of f(x) at x=-5/3 is A. 0 B. 144 C. 1,296 D. 3,888 E. 7,776 I got A
*Saturday, March 14, 2015 at 10:59pm*

**Calculus**

A function f(x) is continuous for all x and has a local minimum at (1,8). Which must be true? A. f'(1)=0 B. f' exists at x=1 C. The graph is concave up at x=1 D. f'(x) is less than 0 if x is less than 1, f'(x) is greater than 0 if x is greater than 1 E. f'(...
*Saturday, March 14, 2015 at 9:53pm*

**Calculus**

The circumference of a circle is increasing at a rate of 2pi/5 inches per minute. When the radius is 5 inches, how fast is the area of the circle increasing in square inches per minute? A. 1/5 B. pi/5 C. 2 D. 2pi E. 25pi
*Saturday, March 14, 2015 at 9:18pm*

**Calculus check**

If f(5)=3 and f'(5)=-2, find the derivative of x^2f(x) at x=5. A. 0 B. -18 C. -12 D. -20 E. -80 I got D
*Saturday, March 14, 2015 at 8:54pm*

** Calculus**

The normal (perpendicular) line to the curve y=sqrt(8-x^2) at (-2,2) has slope A. -2 B. 1/2 C. -1/2 D. 1 E. -1 I got A
*Saturday, March 14, 2015 at 8:51pm*

**calculus trig substitution**

∫ x^3 √(x^2+9) dx If you work it can you write the steps? I really don't like the way my teacher teaches it. Someone else doing it might help.
*Saturday, March 14, 2015 at 8:39pm*

**Calculus**

∫ x^3 √(16-x^2) dx evaluated between [0, 4] I know this is solved using trigonometric substitution, but I'm not sure how to work it. Please show steps so I will understand.
*Saturday, March 14, 2015 at 8:37pm*

**Calculus 2**

∫ tan^2 (x) sec^4 (x) dx ∫ [tan^2 (t) + tan^4 (t)] dt ∫ [1-tan^2 (x)] / [sec^2 (x)] dx Trigonometric integral Please show steps so I can understand!
*Saturday, March 14, 2015 at 8:31pm*

**Calculus check**

The integral of (x^2-4secxtanx) dx= I got x^3/3-4secx+c
*Saturday, March 14, 2015 at 8:18pm*

**Calculus**

In the next questions, a particle is moving along a horizontal line according to the formula: s=2t^4-4t^3+2t^2-1 a) the particle is moving right when A. 0 is less than t is less than 1/2 B. t is greater than 0 C. t is greater than 1 D. 0 is less than t is less than 1/2, t is ...
*Saturday, March 14, 2015 at 8:16pm*

**Calculus**

f(x)=x^n , where n is a positive integer greater or equal to 2. The graph of f(x) will have an inflection point when n is A. Even B. Odd C. Divisible by 3 D. For all values E. For no values
*Saturday, March 14, 2015 at 7:50pm*

**Calculus**

If y=3/(sinx+cosx) , find dy/dx A. 3sinx-3cosx B. 3/(sinx+cosx)^2 C. -3/(sinx+cosx)^2 D. 3(cosx-sinx)/(sinx+cosx)^2 E. 3(sinx-cosx)/(1+2sinxcosx)
*Saturday, March 14, 2015 at 7:36pm*

**Pre-Calculus**

How many parameters in a quadratic function in a vertex form change when you change the location of the vertex? ( P and Q change? The value of the coefficient( a ) may also change?)
*Saturday, March 14, 2015 at 7:31pm*