# Homework Help: Math: Calculus

## Recent Homework Questions About Calculus

**Calculus**

Sand falls from a conveyor belt onto a conical pile at a rate of 6ft/mi^3. The radius of the base is always equal to two-thirds of the pile’s height. At what rate is the height of the pile changing when the radius of the base of the pile is 2 ft? I honestly have no idea how ...

*Sunday, July 3, 2016 by Jace*

**Calculus**

Sketch the graph of the function that has the following properties. f is continuous on (-infinity, infinity). points: (-1,2), (0, 0), (-1,0) f'(x)>0 at (-infinity, -1) f'(-1)=0 f'(x)<0 at (-1, 1) f'(1)=0 f'(x)>0 on (1, infinity) f"(x)<0 on (-infinity, 0) f"(0)=0 f...

*Thursday, June 30, 2016 by Sarah*

**calculus**

the fence around a rectangular compound costs $4 a foot for three of the four sides. the fourth side is the wall of a building, so no fence is needed for that side. we will call the distance of the fence parallel to the wall w for width and the two other sides d for depth. a) ...

*Wednesday, June 29, 2016 by kristi*

**Calculus**

A box with square base and rectangular sides is being designed. The material for the sides costs 20 cents per square inch and that for the too and bottom costs 10 cents per square inch. The box is to hold 150 cubic inches. What dimension of the box will minimize the cost?

*Wednesday, June 29, 2016 by Bella*

**Calculus**

A printed page is to have 1.5 inches margin on all sides. The page should contain 144 square inches of type. What dimension of the page will minimize the area while still meeting these other requirements?

*Wednesday, June 29, 2016 by Sarah*

**Calculus**

A box (with no lid) is to be constructed from a sheet of card board by cutting the squares from corners and folding up the sides. Suppose the original sheet of card board measures 16 inches by 16 inches. What would the size of the squares removed to maximize the volume of the ...

*Wednesday, June 29, 2016 by Anna*

**calculus**

Find the volume generated by revolving about the x-axis the region bounded by the following curves y=sqrt/(4x+3),x=0,x=4, and y=0. (Use "pi" for π).

*Wednesday, June 29, 2016 by SARAH*

**Differential Calculus**

A norman window has the shape of a rectangle surmounted by a semicircle. If the perimeter of the window 10 m, express the area A of the window as the function of width x of the window.

*Tuesday, June 28, 2016 by GRAY*

**Calculus**

Use implicit differentiation to find the derivative of y with reapect to x x^2y-y^2+ln(xy)=1

*Tuesday, June 28, 2016 by Anonymous*

**Calculus - Discontinuity**

What kind of discontinuity is this piecewise function? Removable or jump? f(x) ={ (2x^2 - 5x - 3)/(x-3) if x does not equal 3 ............6............................if x = 3

*Monday, June 27, 2016 by Jane*

**Calculus**

What kind of discontinuity is this: F(x)= (2x^2 - 5x -3)/(x-3) if x does not equal 3 6 if x=3 It is a pieces use function. I thought it was removable but my answer key says it is a jump discontinuity. This is from an exam review and I want to get it right.

*Monday, June 27, 2016 by Bob*

**calculus**

Find the general solution of the equation. 6t*dy/dt+y=sqrt (t),t>0.

*Monday, June 27, 2016 by rebekah*

**calculus**

500-gallon tank initially contains 200 gallons of brine containing 100 pounds of dissolved salt. Brine containing 2 pounds of salt per gallon flows into the tank at the rate of 4 gallons per minute, and the well-stirred mixture flows out of the tank at the rate of 1 gallon per...

*Monday, June 27, 2016 by rebekah*

**calculus**

Given a closed box with surface area = 16 and a square bottom, what value of x will maximize the volume of the box?

*Monday, June 27, 2016 by buni*

**calculus**

What function should be used to minimize the distance between and the point (2, 0)?

*Monday, June 27, 2016 by bunneebud*

**calculus**

Given the area of a rectangle is A = bh, and assuming the rectangle is open on one side, perimeter b + 2h = 40, what formula will maximize the area of the rectangle

*Monday, June 27, 2016 by bunnybud*

**calculus**

a particle is moving along the curve whose equation is" y=x^2? At what point on the curve are the x and y coordinates changing at the opposite rate?

*Monday, June 27, 2016 by scott g*

**Calculus**

The base of a solid is the region bounded by the lines y = 5x, y = 10, and x = 0. Answer the following. a) Find the volume if the solid has cross sections perpendicular to the y-axis that are semicircles. b) Find the volume if the solid has cross sections perpendicular to the ...

*Thursday, June 23, 2016 by Jessica*

**General Physics**

Clarification: this is calculus-based physics, so the methodology is not restricted to trigonometry only. I have two questions, so hopefully I can divide them up nice and evenly. Also, if you know where I should copy and paste proper vector notation from, please tell me so I ...

*Thursday, June 23, 2016 by Justin*

**Calculus**

Related rates: The volume of a cube is increasing at the rate of 40 mm^3/s. How fast is the surface area of the cube increasing when each edge is 10 mm?

*Thursday, June 23, 2016 by anonymous*

**CALCULUS**

State the intercepts, domain and range for y= |0.5x^2-2|.

*Tuesday, June 21, 2016 by Peter*

**CALCULUS**

Let y(t) denote the mass of a radioactive substance at time t.t. Suppose this substance obeys the equation y′(t)=−14y(t). Assume that, initially, the mass of the substance is y(0)=M>0. At what time does half of the mass remain? (Round your answer to 3 decimal ...

*Monday, June 20, 2016 by Sarah*

**Calculus**

A tetrahedron is formed in the rst quadrant by the three coordinate planes and the plane that meets the x-axis at a > 0, the y-axis at b > 0 and the z-axis at c > 0. Compute its volume. Kindly help

*Monday, June 20, 2016 by Asfand*

**Calculus**

The position, p(t), of an object at time t is given. Find the instantaneous velocity at the indicated time c. Also determine whether it is moving forward, backward, or neither at time c. p(t)=2-1/t at c=3

*Monday, June 20, 2016 by Anonymous*

**Calculus**

Find the area under the curve of y=-2x+6 from x=0 to x=3 using 3 strips of equal length using right endpoints. I tried this equation before and my answer was 9 but my teacher said it was wrong? and I also posted this before and Someone who helped me got the same answer. So I'm...

*Friday, June 17, 2016 by Maya*

**Calculus**

Given the function 6x+3y=18, find the area under the curve from x=0 to x=3 using 3 strips of equal length using the right end points. I was working on this and so I made the equation equal to Y=mx+b form so it ends up being Y=-2x+6, and now I am completely confused.. Please ...

*Friday, June 17, 2016 by Maya*

**Calculus**

lim x-->0 ((7-3x^5+x^2sinx)/(5cosx))

*Friday, June 17, 2016 by anonymous*

**calculus**

find the constants a and b so the function is continuous on a real line piecewise function: f(x)={5, if x<= -2; ax+b, if -2<x<3; -5, if x>=3 I know the limit x-->2- is 5 and limit x-->3+ is -5. I don't know how to find the constants

*Friday, June 17, 2016 by anonymous*

**CALCULUS**

∫4x^−1*sin(ln(6x))dx I got 4*[-cos(ln(6x))]+C but its wrong and im not sure why... Please Help!! Thanks

*Thursday, June 16, 2016 by Sarah*

**Calculus**

find the value of a, if it exists, such that the following function is continuous at X = 2. piecewise function f(x)={x^2-3x+1, if x>2; a, if x=2; 3-2x, if x<2 I found the limits from left and right of 2 = -1 so the limit exists but I don't know how to figure out a

*Thursday, June 16, 2016 by Sarah*

**Calculus**

F(x)=2x^2-log(x+5)/√16+x

*Wednesday, June 15, 2016 by Bruno*

**CALCULUS**

Find the derivative of y=4sinx−2cosx

*Wednesday, June 15, 2016 by Sarah*

**calculus**

A rectangular lot is to have an area of 1600m^2. Find the shortest that can can reach the building with one end resting on the ground outside the wall

*Wednesday, June 15, 2016 by montefalco*

**Calculus**

The function f is continuous on the interval [4, 15], with some of its values given in the table above. Estimate the average value of the function with a Right Rectangle Approximation, using the 4 intervals between those given points. x 4 9 11 14 15 f(x) -6 -11 -18 -21 -25 -11...

*Tuesday, June 14, 2016 by Vikram*

**Calculus- PLEASE HELP**

A rectangular piece of tin has an area of 1334 square inches. A square tab of 3 inches is cut from each corner, and the ends and sides are turned up to make an open box. If the volume of the box is 2760 cubic inches, what were the original dimensions of the rectangular piece ...

*Tuesday, June 14, 2016 by James*

**Calculus**

A rectangular piece of tin has an area of 1334 square inches. A square tab of 3 inches is cut from each corner, and the ends and sides are turned up to make an open box. If the volume of the box is 2760 cubic inches, what were the original dimensions of the rectangular piece ...

*Monday, June 13, 2016 by James*

**Calculus- Reiny**

Thanks for the help, but do you understand what Im suppoosed to graph on 2D d) Use a graphing calculator to sketch the graph of y = V(x). Use the viewing window [0, 24, 4] by [-2500, 4000, 500]. Then use the 2 nd – TRACE – maximum feature to calculate its maximum point. ...

*Monday, June 13, 2016 by James*

**Calculus**

A rectangular piece of tin has an area of 1334 square inches. A square tab of 3 inches is cut from each corner, and the ends and sides are turned up to make an open box. If the volume of the box is 2760 cubic inches, what were the original dimensions of the rectangular piece ...

*Monday, June 13, 2016 by James*

**Calculus**

let f(x)=2x-7. Use the rigorous definition of limit to show that lim x-->4 f(x)=1

*Monday, June 13, 2016 by Sarah*

**AP Calculus AB**

The function f is continuous on the interval [4, 15], with some of its values given in the table above. Estimate the average value of the function with a Right Rectangle Approximation, using the 4 intervals between those given points. x 4 9 11 14 15 f(x) -6 -11 -18 -21 -25 -11...

*Monday, June 13, 2016 by Ryann*

**Calculus**

lim x--> 2+ (tan(pi/x))

*Sunday, June 12, 2016 by Anonymous*

**Calculus**

Two positive numbers have the property that their product is 2 and their sum is as small as possible. Find their sum.

*Friday, June 10, 2016 by Dylan*

**Calculus**

Use pinching theorem to evaluate lim x-->1 ((x-1)sin(1/x-1)) I'm confused in the pinch theorem analytically

*Thursday, June 9, 2016 by Anonymous*

**Pre-Calculus**

Your computer supply store sells two types of laser printers. The first type, A, has a cost of $86 and you make a $45 profit on each one. The second type, B, has a cost of $130 and you make a $35 profit on each one. You expect to sell at least 100 laser printers this month and...

*Wednesday, June 8, 2016 by Alexa*

**Pre-Calculus Matrix**

Use Gaussian elimination to find the complete solution to the system of equations, or state that none exists. Show your work. 4x - y + 3z = 12 x + 4y + 6z = -32 5x + 3y + 9z = 20 4 -1 3 12 1 4 6 -32 5 3 9 20 I believe that the solution does not exist and how can I prove that?

*Wednesday, June 8, 2016 by Alexa*

**Pre-Calculus**

Solve the system of equations using matrices. Use Gaussian elimination with back-substitution. x + y + z = -5 x - y + 3z = -1 4x + y + z = -2 I really need help.. 1 1 1 -5 1 -1 3 -1 4 1 1 1 -2 I've done so many different methods to solve this and I get stuck..

*Tuesday, June 7, 2016 by Alexa*

**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...

*Tuesday, June 7, 2016 by Alexa*

**pre-calculus**

A plane flies at a speed of 150mph at an angle of 10 degrees, after 6 seconds, the plane keeps the same speed but changes to an angle 18 degrees. How long in minutes would it take the plane to travel to a cruising altitude of 30,000 feet?

*Tuesday, June 7, 2016 by Marc*

**maths-calculus help me**

differentiate Arccosh(x^2+1)*dy/dx if y=arcsinh(coth(x^2) plz showfull work i plead my brain is fried

*Sunday, June 5, 2016 by am in trouble*

**Calculus**

which of the following is equivalent to integral (a,b) k*f(x)+C)dx where k and C are constants k integral (a,b)(f(x)+C)dx ***** intergral (a,b)kdx + intergral (a,b)f(x)dx+ intergral (a,b) Cdx k integral (a,b)f(x)+ integral (a,b) Cdx integral (a,b) kdx * integral (a,b) f(x) dx...

*Friday, June 3, 2016 by Kevin*

**Calculus**

Find F'(x) for F(x)= integral[from 1 to x] of cos(t^3)dt

*Friday, June 3, 2016 by Kevin*

**Calculus**

lim (x--> infinidy) x^2/ln(x)= -1 0 1 e does not exist

*Friday, June 3, 2016 by Kevin*

**Calculus**

Which of the following grows faster than e^x as x--> infinity x^4 ln(x) e^-x 3^x .5e^x

*Friday, June 3, 2016 by Kevin*

**calculus**

Find the point on the line 4x+2y+5=0 which is closest to the point (-2,-1)

*Thursday, June 2, 2016 by Anonymous*

**Calculus**

Find the area bounded by the parabola 8+2y-y^2 and the lines y=-1 y=3

*Thursday, June 2, 2016 by Eli*

**Pre-Calculus**

Use Gaussian elimination to find the complete solution to the system of equations, or state that none exists. Show your work. 4x - y + 3z = 12 x + 4y + 6z = -32 5x + 3y + 9z = 20 Please help me..

*Thursday, June 2, 2016 by Liz*

**Pre-Calculus**

Solve the system by the substitution method. Show your work. 2y - x = 5 x2 + y2 - 25 = 0 I solved the problem but I got it wrong for some reason..can you solve it step by step?

*Thursday, June 2, 2016 by Liz*

**Pre-Calculus**

Locate the foci of the ellipse. Show your work. x^2/36+y^2/11=1 c^2=a^2-b^2 c^2=36-11 c^2=25 c= ± sqrt25 c= ±sqrt5*5 is this correct?

*Thursday, June 2, 2016 by Liz*

**Pre-Calculus**

Assume that x, y, and z are positive numbers. Use the properties of logarithms to write the expression 2lnx - 6lny + 1/3ln e^12 as a simplified logarithm. Is this 2lnx - 6lny + 4, or can it be simplified further?

*Thursday, June 2, 2016 by Anonymous*

**Pre-Calculus**

How do I find the domain of K(x) = x(32 - 2x)^2?

*Thursday, June 2, 2016 by Anonymous*

**Calculus**

A base of a solid is the region bounded by y=e^-x, the x axis, the y axis, and the line x=2. Each cross section perpendicular to the x-axis is a square Find the volume of the solid

*Thursday, June 2, 2016 by Hannah*

**Pre-Calculus**

Find a polynomial with the zeros -1, 7, sqrt2, and -(sqrt2). Can this be f(x) = x^4 - 6x^3 - 9x^2 + 12x + 14?

*Thursday, June 2, 2016 by Anonymous*

**Pre-Calculus**

Find the vertical asymptotes, if any, of the graph of the rational function. Show your work. f(x) = (x-4)/(x(x-4)) (x-4)/x(x-4) the common factors cancel out and all is left is f(x)= 1/x... how do I solve this problem?

*Wednesday, June 1, 2016 by Liz*

**Math (Calculus)**

Find the positive value of the parameter t corresponding to a point on the curve parametrized by {x= t^2 +3 ; y=t^2+t for which the tangent line passes through the origin. I tried with 2t+3 and 2t+1 but it isn't successful

*Monday, May 30, 2016 by Anonymous*

**Math Calculus I**

let f(x)= 6sin(x)/(2sin(x)+6cos(x)) The equation of the tangent line to y= f(x) at a= pi/6 can be written in tthe form y=mx+b where m=? b=? I found the f': (9*(cos^2(x)+sin^2(x)))/(3cos(x)+sin(x))^2 but i don't know how to fill it into the form. Can anyone help me? ...

*Monday, May 30, 2016 by Anonymous*

**Integral calculus**

find the area of the surface generated by revolving about x-axis the upper half of the ellipse 4x^2 + 16y^2 = 64

*Sunday, May 29, 2016 by Anonymous*

**Pre calculus**

olve the system of equations using matrices. Use Gaussian elimination with back-substitution. x + y + z = -5 x - y + 3z = -1 4x + y + z = -2 I need it explained to me, how do I do this?

*Sunday, May 29, 2016 by Kim*

**Calculus**

Two ships leave the same port at noon. Ship A sails north at 12 mph, and ship B sails east at 19 mph. How fast is the distance between them changing at 1 p.m.? (Round your answer to one decimal place.)

*Saturday, May 28, 2016 by Chuck*

**Calculus**

Solve the differential equation: dy/dx = (3x^2) / (y+1) with initial conditions x = -1, y = 2 I have: ∫y + 1 dy = ∫3x^2 dx (y^2 / 2) + y = x^3 + C (2^2 / 2) + (2) = (-1^3) + C? 4 = -1 + C 5 = c (y^2 / 2) + y = x^3 + 5 Is this correct?

*Friday, May 27, 2016 by Omar*

**Calculus**

Volume created when the area bounded by the curve y = 1/x, the x-axis, and the lines x = 1 and x = 4 is rotated about: a) the x-axis: 2.356 units^3 Is this correct? b) the line y = 5 I'm not sure how to do this one.

*Friday, May 27, 2016 by Aria*

**Calculus**

when x intercept -3, point P(2,5,7) and Q(1,10,14) how to find x,y and z?

*Friday, May 27, 2016 by ChrismB*

**MATH - CALC**

Use calculus and algebraic methods to do a complete analysis (i.e., intervals of increase and decrease, intercepts, critical points, points of inflection, and intervals of concavity) for each of the following functions and then sketch a graph of the function. (19 marks) ƒ(x...

*Friday, May 27, 2016 by Ab*

**Calculus**

Solve the differential equation dy/dx = √[(x^3)(y)] with initial conditions x = 1, y = 2 so far i got y = (x^5)/25 + c so do i plug in 2 = (1^5)/25 + c 2 - (1/25) = c c = 49/25 = 1.96 is this correct?

*Thursday, May 26, 2016 by Mike*

**Calculus**

A particle with an initial velocity of -6 has its acceleration defined by a(t) = 2t+1. t is in seconds. find: a) its velocity equation b) the total distance traveled by the particle during its first 5 seconds of travel a) v(t) = t^2 + t - 6 b) 24.17 units is this correct?

*Thursday, May 26, 2016 by Yani*

**calculus-again frustrated-looking for steve asap**

if sinh(y)=[4sinh(x)-3)/(4+3sinh(x)] show that dy/dx=5/(4+3sinh(x)] step plz i plead

*Thursday, May 26, 2016 by dam*

**calculus-help me sir~steve**

show that 2f''(t)-f'(t)-f(t)=sin(t)-cos(t) where f(0)=f'(0) has the solution (-2/5)e^(-t/2)-(1/5)sin(t)+(2/5)cos(t) using laplace tranformation plz plz plz show step by step

*Thursday, May 26, 2016 by dam*

**Calculus**

Find the area of the region bounded by the curves y = x^(-1/2), y = x^(–2), y = 1, and y = 3. a) (1/2)(3)^1/2 + (4/3) b) 2*(3)^1/2 - (8/3) c) (1/2)(3)^1/2 - (32/3) d) 2*(3)^1/2 - (32/3) e) (8/3) - 2*(3)^1/2 So one thing that is throwing me off on this question is that I ...

*Tuesday, May 24, 2016 by Emily*

**Calculus**

Design an Advanced U substitution problem whose answer must be exactly 6 and can be solved without using calculator?

*Tuesday, May 24, 2016 by ChrismB*

**calculus-help.. .Me**

if y=e^(-kt)[Acosh(qt)+Bsinh(qt)] where A,B,q and k are constant show that d^2y/dt^2+2kdy/dt+(k^2-q^2)y=0 step plz thanks

*Tuesday, May 24, 2016 by samuel*

**integral calculus**

A cylindrical tank of radius 3 ft length 8 ft is laid out horizontally .The tank is half full of oil that weighs 60 pounds per cubic foot. a.)determine the work done in pumping out oil to the top of the tank. b.)determine the work required to pump out the oil to leave 4 feet ...

*Sunday, May 22, 2016 by jhay*

**Calculus**

please solve it let f be the function defined over { 0 , ∞ ) as ∫ f(x) = x(ln(x)-1)^2 for x>0 and let (c) be its representative curve , we admit that f is continous at x=0 a ) determine lim f(x) / x as x approaching 0 b) find lim f(x) as x approaching infinity ...

*Saturday, May 21, 2016 by Darker*

**calculus**

Find the domain for the particular solution to the differential equation dy dx equals the quotient of 3 times y and x, with initial condition y(1) = 1.

*Friday, May 20, 2016 by Bree*

**Calculus (Integration proving)**

Show that 0 <= [(integral)(integral, r to none)sin(pi)xcos(pi)y dA] <= 1/32 where R = [0,1/4]x[1/4]x[1,2]. Thank you.

*Friday, May 20, 2016 by Tony*

**calculus**

If the graph of f " (x) is continuous and has a relative maximum at x = c, which of the following must be true? The graph of f has an x-intercept at x = c. The graph of f has an inflection point at x = c. The graph of f has a relative minimum at x = c None of the above is ...

*Friday, May 20, 2016 by Bree*

**calculus**

R is the first quadrant region enclosed by the x-axis, the curve y = 2x + a, and the line x = a, where a > 0. Find the value of a so that the area of the region R is 18 square units.

*Friday, May 20, 2016 by Bree*

**Pre-Calculus**

A drug is administered every 6 hours. The kidneys eliminate 55% of the drug over that period. The initial dose is 210 mg. Repeated dosage is 70 mg What is the “Difference equation”? Find the first seven terms of the of the solution sequence. Round to two digits each ...

*Thursday, May 19, 2016 by Anonymous*

**Pre-Calculus**

A drug is administered every 6 hours. The kidneys eliminate 55% of the drug over that period. The initial dose is 210 mg. Repeated dosage is 70 mg What is the “Difference equation”? Find the first seven terms of the of the solution sequence. Round to two digits each ...

*Thursday, May 19, 2016 by Anonymous*

**Calculus**

An observer 150 feet from point C, where a weather balloon has been released. The balloon rises vertically at a rate of 8ft/sec/. At the very instant the balloon is 250 above ground how far is it from the observer? How Quickly is it moving away from the observer at that moment...

*Wednesday, May 18, 2016 by Peter*

**Calculus**

A car accelerates from rest at 1.1+2(t^1/2) m/h per second for 9 seconds find velocity after 9 seconds.

*Wednesday, May 18, 2016 by John*

**calculus**

use logarithmic differentiation to find dy/dx for: [(x^2)(e^2)(x)] / [3√(2x-5)]

*Wednesday, May 18, 2016 by mike*

**Calculus**

Write a differential equation equivalent to "A chemical decomposition proceeds at a rate equal to the square of the amount of chemical present"

*Wednesday, May 18, 2016 by Arie*

**Calculus**

find the particular solution of the differential equation that satisfies the conditions: f''(x)=sin(x)+e^(2x) f(0)=1/4, f'(0)=1/2

*Wednesday, May 18, 2016 by Arie*

**Calculus**

solve the equation y'=(sqrt(x))/2y

*Wednesday, May 18, 2016 by Arie*

**Calculus**

given d/dx[f(2x)]=f'(x) and f'(1)=1 find f'(2) the choices are 1/4, 1/2, 3/4, 3/2, or 5/2 if it helpes

*Wednesday, May 18, 2016 by Arie*

**Calculus**

Find the particular solution of differential equations that satisfies the initial condition dx/dy=e^(x+y) x(1)=0 I know you have to get all the y and dy on one side and x and dx on the other so you can intagrate and stuff, but im having trouble getting there

*Wednesday, May 18, 2016 by Arie*

**Differential Calculus**

From a faucet, a constant inflow of water is to fill a conical vessel 15 feet deep and 7.5 feet in diameter at the top. water is rising at the rate of 2 feet per minute when the water is 4 feet deep. what is the rate of inflow in ft^3/min?

*Wednesday, May 18, 2016 by Patricia*

**Calculus**

Inflection point of 3y=x^3+3x^2-9x+3

*Wednesday, May 18, 2016 by Shery*

**Calculus**

I need help I have to submit work at 12 est time

*Tuesday, May 17, 2016 by WALE*

**Calculus**

Need help with a few questions

*Tuesday, May 17, 2016 by WALE*

**integral calculus**

Find the area between the curves y=5x and 2y=5x^2

*Tuesday, May 17, 2016 by Dessa*