Helga

If f(x) = x ln(1+x) estimate the value of ln (2.1) given that ln2 = 0.6931.

13 years ago

Differentiate x^2*y^2 = (y+1)/(x+1) in terms of x and y. PS My answer is unfortunately at odds with that provided by the authors of the book (i.e. -y (y+1) (3x+2) all over x (x+1) (y+2), and I don't know whether it's a misprint or my method is wrong.

13 years ago

It may look lame but I can't work out how to solve (-9) sqrt(4-x^2) = 4x + 5sqrt2. I need some guidance, please.

13 years ago

A right circular cone has a constant volume. The height h and the base radius r can both vary. Find the rate at which h is changing with respect to r at the instant when r and h are equal.

13 years ago

A container in the form of a right circular cone of height 16 cm and base radius 4 cm is held vertex downward and filled with liquid. If the liquid leaks out from the vertex at a rate of 4 cm^3/s, find the rate of change of the depth of the liquid in the...

13 years ago

You are a forensic doctor called to a murder scene. When the victim was discovered, the body temperature was measured and found to be 20°C. You arrive one hour later and find the body temperature at that time to be 18°C. Assuming that the ambient temperat...

13 years ago

The coefficient of x^2 in the expansion of (4-3x)^n as a series of ascending powers of x is -9/64. Show that n satisfies the equation 4^(n+1)=2/[n(1-n)] and hence verify that n=1/2. I can do the first part of the problem: 4^n*3^2*n(n-1)/2!*2^4=-3^2/2^6 4*...

13 years ago

How do I calculate 4^n=1/(2(n-n^2))? Thanks.

13 years ago

A bicycle tire is filled with air to a pressure of 610 kPa at a temperature of 19 oC. Riding the bike on asphalt on a hot day increases the temperature of the tire to 58 oC. The volume of the tire increases by 4.0%. What is the new pressure in the bicycle...

13 years ago

The oxides of Group 2A metals (symbolized by M here) react with carbon dioxide according to the following reaction: MO(s) + CO2(g)  MCO3(s) A 2.85-g sample containing only MgO and CuO is placed in a 3.00-L container. The container is filled with CO2 to...

13 years ago

when 20 ml of a .10 M silver nitrate solution is mixed with 25 ml of a 0.080 M solution of sodium sulfide, producing a precipitate of silver sulfide, what is the final concentration of sulfide ion?

12 years ago

In the titration of 20.00 mL of 0.175 M NaOH, calculate the number of milliliters of 0.200 M HCl that must be added to reach a pH of 12,55. I know the answer is 11,9 mL but I don't know how to calculate it.

11 years ago

8 people are going to sit on 6 chairs. Two of them John and Kelly can't sit next to each other. How many ways can you put the people to seats? The answer is 10080, but I can't figure out how to calculate it.

11 years ago

One of the reactions that occurs in a blast furnace, in which iron ore is converted to cast iron, is Fe2O3 + 3CO → 2Fe + 3CO2 Suppose that 1.59 × 103 kg of Fe is obtained from a 2.54 × 103 kg sample of Fe2O3. Assuming that the reaction goes to completion,...

10 years ago

A helicopter above the ground is descending at 3.5 m/s. It drops a package from rest(relative to the helicopter). Just before it hits the ground the package is falling at a rate of 13.4 m/s relative to the ground. Find the velocity of the package relative...

7 years ago

A Dodge Stealth is driving at 70 mph on a highway. It passes a BMW going the same direction. The BMW is moving 7 mph backward relative the Dodge. What is the velocity of the BMW? Let the positive direction be forward. -63 mph -77 mph 77 mph 63 mph A helic...

7 years ago

4. In a shopping mall, two elevators pass each other moving in opposite directions. Each elevator to the other is 10 m/s. What is the velocity of each elevator relative to a person standing on the ground? One elevator has a velocity of 5 m/s and the other...

7 years ago

Given that ray BD bisects angle ABC, and that angle ABD is 4x-10, and segment CBD is 2x + 4, find the measures of angles ABC, ABD, and DBC.

5 years ago

Seurities Fair Value Adjustment (Trading) Account Securities Fair Value Adjustment (Trading) + (Gain) - (Loss) 25,000 Ending Balance 12/31/2009 Adjusting entry on 12/31/2010 35,000 Ending Balance on 12/31/2010 10,000 40,000 Adjusting entry on 12/31/2011 3...

14 years ago

Shame about your computer. Don't want to die wondering ;)

13 years ago

Oh, I see. So to make an estimate you'd have to make an assumption of ambient temperature, right? Assuming constant ambient temperature of 10°C, the time of death could be estimated to be at around 4.45 (i.e 4 to 4 1/2) hours before discovery. Is that cor...

13 years ago

Is there a more elegant solution than trial and error?

13 years ago

Can you put the figures into the equation for me, because I do not quite understand this?

10 years ago

They are all correct except for #3 I don't know the answer but I just took the exact same quiz, used your answers and got them all right except #3.

3 years ago