MATH DOCS Flashcards
Three sides of a trapezoid are each 8 cm long. How long is the 4th side, when the area of the trapezoid has the greatest value?
- A. 16 cm
Sand is pouring to form a conical pile such that its radius is always twice the height, if the volume of a conical pile is increasing at a rate of 2 cu. m/s. How fast if the height is increasing when the height is 4m?
C. ⅛ π – ⅛ pi m/s
Find the radius of curvature of y = x^3 at the point (1,1).
- C. 5.27
1A rectangular field is fenced off, an existing wall being used as one side. If the area of the field is 7,200 sq. ft, find the least amount of fencing needed.
- C. 240 ft
If z = xy^2, and x changes from 1 to 1.01, and y changes from 2 to 1.98, find the approximate change in z.
- A. -0.0404
Find y’ if y-acrsin(cosx)
- A. -1
Evaluate Л tan(theta) In sec(theta) d(theta)
- D. ½ ln(secθ)^2 + C
Find the curve surface area of the solid generated by revolving the part of the curve y = x2 from (0,0) to (√6,6) about the y-axis.
B. 62π/5 sq. units
Find the volume of the solid generated by revolving the area of the circle x^2+y^2=36 on the second quadrant about the line y + 10=0
- D. 2229
What is the area (in square units) bounded by the curve y^2=x and the line x-4=0?
- C. 32/3
What is the area within the curve r2 = 16 cos 0?
- D. 32
Find the area bounded by the y-axis and x = 4-y^2/3
- A. 25.6
Evaluate ∫1,0 ∫y^2, y ∫lnx,0 ye^z dzdxdy
- C. 1/24
A solid is formed by revolving about the y-axis, the area bounded by the curve x^3=y, the y-axis and the line x=8 Find Its Centroid
- A. (0, 4.75)
Determine the moment of inertia of the area bounded by the curve x2 = 4y, the line x-4=0 and the x-axis with respect to the y-axis
- A. 51.2
The rate of population growth of a country is proportional to the number of inhabitants. If a population of a country now is 40 million and expected to double in 25 years, in how many years is the population be 3 times the present?
- A. 39.62 years
A thermometer reading 18 °C is brought into a room where the temperature is 70 °C; 1 minute later the thermometer reading is 31 c. 18.64yrs °C. Determine the thermometer reading 5 minutes after it is brought into the room.
- D. 57.66 °C
Water at 100°C cools in 5 minutes to 70°C in a room at 20°C. What will be the temperature of the water at the end of another 5 minutes?
- B. 51.25°C
A thermometer which has been at the reading of 70°F inside a house is placed outside where the air temperature is 10°F. Three minutes later it is found that the thermometer reading is 25°F. Find the thermometer reading after 6 minutes.
- C. 13.75 °F
In a tank are 100 liters of brine containing 50 kg total of dissolved salt. Pure water is allowed to run into the tank at the rate of 3 d. 11.75 °F liters a minute. Brine runs out of the tank at the rate of 2 liters a minute. The instantaneous concentration in the tank is kept uniform by stirring. How much salt is in the tank at the end of one hour?
- B. 19.53 kg
Evaluate the value of tanh(jpi/3)
- C. j 1.732
Find a0 for the equivalent Fourier series of x^2 over the interval -pi to pi
C. π ^2/3
Find the interval of convergence (-1)^n n/ 4^n (x+3)^n
- A. -7<x<1