Most popular questions and responses by Tan
  1. calculus

    assume that during the first 3 minutes after a foreign substance is introduced into the blood,the rate R'(t) at which new antibodies are produced(in thousands of antibodies per minute) is given by R'(t)=t/(t^2+1) where t is in minutes.find the total

    asked on March 19, 2013
  2. Chemistry

    When 0.100 mol CaCO3(s) and 0.100 mol CaO(s) are placed in an evacuated sealed 10.0 L container and heated to 385 K, P(CO2) = 0.220 atm after equilibrium is established. CaCO3(s) CaO(s) + CO2(g) 0.05 atm CO2(g) is then removed from the container. What is

    asked on November 18, 2014
  3. Math

    Standing 4ft from the mirror lying on the ground ground, Palmer who's eye height is 5ft 9inches, can reflection the top of the tree. He measures the mirror to be 24ft from the tree. How tall is the tree?

    asked on December 30, 2016
  4. Math

    A ribbon is 12 3/8 feet long. Into how many 3/4 -foot pieces can it be cut?

    asked on October 25, 2016
  5. physics

    As shown in the figure, a bullet of mass m and speed v passes completely through a pendulum bob of mass M. The bullet emerges with a speed of v/2. The pendulum bob is suspended by a stiff rod of length ℓ and negligible mass. 2.1 Derive an expression for

    asked on June 8, 2016
  6. Math

    In 1924, the temperature in Fairfield, Montana, dropped from 63 degrees to -21 degrees in 12 hours. What was the average hourly change in temperature. Thank you

    asked on October 25, 2016
  7. Math

    A car engine is running at 5000 revolutions per minute. (a) how many revolutions are made in one hour? (b)if this engine uses 10 litres of fuel in one hour, how much fuel, in millilitres,does it use for every revolution?

    asked on August 18, 2015
  8. Science

    Acetylene gas combust.how many grams of carbon dioxide and grams of water are produced when 52.0 g of acetylene burns ?

    asked on April 11, 2016
  9. Fianance

    A tax-exempt bond was recently issued at an annual 8 percent coupon rate and matures 20 years from today. The par value of the bond is $1,000.

    asked on December 3, 2015
  10. Trigo

    Find all angles between 0 and 2 phi inclusive which satisfy cot 2z = 1 + cot z

    asked on February 10, 2019
  11. 6th grade

    Pet Parade: Mr. James has 14 cats, dogs and guinea pigs. What are all the combinations he could have?

    asked on October 17, 2014
  12. Chemistry

    In a qualitative analysis, the test for the presence of Cu^2+ ion is the formation of the bright blue complex ion Cu(NH3)42+. What is the equilibrium concentration of Cu2+ when 1.0 mL of 0.200 M Cu^2+ is combined with 1.0 mL of 15.0 M NH3? (Kf Cu(NH3)4^2+

    asked on July 8, 2017
  13. Math

    Jared bought a cell phone for $42. Juanita spent 1 1/2 times as much. How much did she spend? Thank you very much!

    asked on October 14, 2016
  14. math

    Solve the equation 4x^3 + 32x^2 + 79x + 60 =0 given that the root is equal to the sum of the other two roots. (Hint: set roots as alpha, beta, gamma)

    asked on September 4, 2015
  15. chemistry

    what's the discussion for determine BaCl2.2H2O in lab report

    asked on June 11, 2014
  16. Science chemistry

    Which compound has the melting point of -23 degree Celsius and boiling point of 77 degree Celsius ? Thx....

    asked on June 20, 2016
  17. Math

    Last semester, a certain professor gave 36 As out of 390 grades. If one of the professor's students from last semester were selected randomly, what is the probability that student received an A? (Assume that each student receives one grade.)

    asked on March 12, 2013
  18. Physics

    a 2 centimeter diameter ball of 50 grams rolls at constant velocity across a table. it takes 4 seconds to travel 3 meters. Sketch graph of horizontal position, velocity and acceleration.

    asked on December 5, 2012
  19. ACCT

    The question is: In the journal provided, prepare year- end adjustments for the following situations. Omit explanations. a. accrued interest on notes receivable is $105 b. of the $12,000 received in advance of earning a service, one third was still

    asked on March 1, 2012
  20. english

    how to write instructions for turning someone into a toad

    asked on June 27, 2009
  21. math

    Write a quadractic equation having given equations? -9,9i

    asked on November 15, 2012
  22. Ap World

    what does colonial legacy mean?

    asked on April 26, 2012
  23. probability

    1. The time it takes a student to cycle to school is normally distributed with a mean of 15 minutes and a variance of 2. The student has to be at school at 8.00a.m. At what time should the student leave her house so that she will be late only 4% of the

    asked on April 10, 2011
  24. geometry (high school)

    if there are two tangent circles that have two external tangent lines that intersect at a 60 degree angle, what is the ratio of the radii.

    asked on February 27, 2011
  25. Geometry

    Hi, I have to use algebra to find the coordinates of the point where two lines intersect, the first line passes through the points 4,3 and 10,0 and the second line is y=6. Any ideas would be very much appreciated, many thanks

    asked on July 14, 2010
  26. math

    When two digits of thbase 10 representation of an inteer are intercharged, the diference bewen the old number and the new number is divisible by 9. Why? What happens in other bases? 10A + B - 10B -A= difference. This reduces to 9A - 9B 9(A-b)= difference.

    asked on January 20, 2007
  27. Physics

    The driver of a sport car pushed down the accelerator so that the engine pushes the care forward with a force of 2500N,s tarting from rest. How fast the car can go after 20s later? I have tried this by using v=u+at but i don't have a. From F=ma, i cant get

    asked on August 28, 2016
  28. MATH

    You would like to construct a 400-square-foot rectangular garden along your driveway. The fencing on the driveway side costs $15 per linear foot, while the fencing for the other three sides costs $8 per linear foot. Write an expression for the cost of the

    asked on October 10, 2015
  29. english

    Would Culture, Heroism, and Supernatural Forces in Beowulf be a good topic for an expository essay on Beowulf being an epic poem?

    asked on December 5, 2011
  30. Chemistry

    An unknown mass of caco3 was added to an excess of 2mol/dm3 hcl. Calculate the total volume of co2 evolved.

    asked on December 4, 2015
  31. math

    Consider that the age, x, of a unicorn in human equivalent years can be given by the formula f(x) = - 0.001618x4 + 0.057326x3 – 1.1367x2 + 11.46x + 2.914. When a unicorn is 2.5 years old, what is its age in human equivalent years? What about when it is

    asked on July 17, 2011
  32. Algebra

    Could someone tell me the solution for x^2 - 3x = 0, i know x = 3 but I just need to know how to get there please

    asked on May 16, 2010
  33. physics

    what would be the significance of the photoelectric effect graph if it a) passed through the origin b) had a positive y intercept

    asked on April 28, 2010
  34. Math

    Juana paid $1,200 for a sofa. The price of the sofa Ben purchased was 3/5 the price that Juana paid. How much did Ben pay for his sofa?

    asked on October 20, 2016
  35. math


    asked on August 3, 2015
  36. Math/modelling

    Hi, I have a linear model with equation p =5.1t - 28, which concerns breeding pairs of birds where p is the number of breeding pairs and t is the year. I need to use this model to estimate the number of breeding pairs in year 15. I would assume to do this

    asked on July 13, 2010
  1. math


    posted on June 27, 2016
  2. Physics


    posted on March 11, 2016
  3. MATH

    Thank you Steve :)

    posted on October 11, 2015
  4. calculus

    i don't understand this part:dt/(t^2 + 1) = (1/2)ln(t^2 + 1)

    posted on March 19, 2013
  5. Math homework

    when given 5,5,5,5,5 using the order of operations and parenthesesto make a true expression where would i place my -,+ *,/ to make the answer equal 1

    posted on September 28, 2010