deel

Most popular questions and responses by deel
  1. math

    The stiffness S of a rectangular beam is proportional to its width (w) times the cube of its depth/height (h). find the dimensions (i.e.: w and h) of stiffest beam that can be cut from a log which has a circular cross-section with diameter of 12-in.

    asked on August 9, 2012
  2. math

    Please help me to find an equation for the tangent to the curve xsin2y=ycos2x at the point (phi/4, phi/2)

    asked on August 13, 2012
  3. math

    In a room of 20.000 ft^3 of air, 600 ft^3 of fresh air flows in per minute, and the mixture (made practically inform by circulating fans) is exhausted at a rate of 600 cubic feet per minute (cfm). What is the amount of fresh air inside the room y(t) at any

    asked on August 8, 2012
  4. math

    A tank contains 50 gallons of a solution composed of 90% water and 10% alcohol. A second solution containing 50% water and 50% alcohol is added to the tank at rate of 4 gallons per minute. As the second solution is being added, the tank is being drained at

    asked on August 10, 2012
  5. math

    A right circular cylinder of radius r and height h is inscribed in a right circular cone of radius R and height H, as shown on the right figure. Find the value of r (in terms of R and H) that maximizes the total surface area of the cylinder (including top

    asked on August 11, 2012
  6. math

    how to find the following limit : lim lnx/lgx x->infinity

    asked on August 21, 2012
  7. math

    find the derivatives, dy/dx for the folowing function : y=ln(cos(0.5)+(sin(x^2+3))^1/3)

    asked on August 25, 2012
  8. math

    find the derivatives, dy/dx, for the following functions : y=(1+sin^2{2 exp (3x)})^5y please help me to solve this assignment. thank's

    asked on August 20, 2012
  9. math

    please help me how to solve the integral sinx/x dx from 0 to infinite : ∫_0^∞▒〖sin⁡x/x dx〗 thank you

    asked on March 24, 2013
  10. math

    consider a 2D mirror has a parabolic profile of y = (x-3)^2 + 5 facing toward y^+ direction. Prove that any beam of light in y^- direction that this hits the mirror will be reflected toward a particular point (i.e. known as the focus of parabolic mirror.

    asked on September 17, 2012
  11. linear algebra

    in order to grow a certain crop, it is recommended that each square foot of ground be treated with 10 units of phosphorous, 9 units of potassium, and 19 units of nitrogen, suppose that there are three brands of fertilizer on the market - say brand X, brand

    asked on November 11, 2012
  12. math

    please help me to solve this assignment : consider a 2D mirror has a parabolic profile of y = (x-3)^2 + 5 facing toward y^+ direction. Prove that any beam of light in y^- direction that this hits the mirror will be reflected toward a particular point (i.e.

    asked on September 18, 2012
  1. math

    thank's steve :)

    posted on August 21, 2012
  2. math

    yes i'm sure..the assignment like that.

    posted on August 20, 2012
  3. math

    thanks for your help :)

    posted on August 11, 2012
  4. math

    y(t)=amount of alcohol in the tank at time t dy/dt =y’(t) = alcohol inflow rate – alcohol outflow rate = 4 - 5(y/50) =200 - 5y/50 = 5 (40-y)/50 dy/dt = 5 (40-y)/50 Separate variable and integrate : dy/(40-y) = 5/50dt -ln(40-y) = 0.1t + C ln(40-y)

    posted on August 11, 2012
  5. math

    oke thanks, i'ill try it

    posted on August 11, 2012
  6. math

    thanks for your help

    posted on August 10, 2012
  7. math

    yes i understand now, thanks for your help

    posted on August 9, 2012
  8. math

    thanks for your help

    posted on August 9, 2012
  9. math

    h^3=s/kw h^3=s/k(12-h) sorry, I'm still confused how to get the function of h. please help me to complete the assignment. thank you

    posted on August 9, 2012