Exam 4: Exponential and Logarithmic Functions

arrow
  • Select Tags
search iconSearch Question
  • Select Tags

Use the definition of the logarithmic function to find xx if logx512=3\log _ { x } 512 = 3 .

Free
(Essay)
4.8/5
(40)
Correct Answer:
Verified

logx512=3\log _ { x } 512 = 3 \Leftrightarrow x3=512x ^ { 3 } = 512 \Leftrightarrow x3=83x ^ { 3 } = 8 ^ { 3 } \Leftrightarrow x=8x = 8

Find the solution of the equation 2x/2=0.012 ^ { x/2 } = 0.01 correct to four decimal places.

Free
(Multiple Choice)
4.7/5
(27)
Correct Answer:
Verified

A

If the pH readings of an unknown substance is pH =10.4= 10.4 , find the hydrogen ion concentration. 

Free
(Essay)
4.8/5
(40)
Correct Answer:
Verified

pH =log[H.]=10.4= - \log \left[ \mathrm { H } ^ { .} \right] = 10.4 \Leftrightarrow [H.]=1010.4\left[ \mathrm { H } ^ {.} \right] = 10 ^ { - 10.4 } M 4.0×1011\approx 4.0 \times 10 ^ { - 11 } M

The population of a certain country was 2,345,2352,345,235 in 19851985 and 3,458,3773,458,377 in 1995.1995 . Assume that the growth is exponential. (a) Find a formula for the population tt years after 1985.1985 . (b) Find the time required for the population to double. (c) Use the data to predict the population in the year 2005.2005 .

(Essay)
4.8/5
(35)

Find the solution of the exponential equation e[(x/4)1=15e ^ { [ ( x / 4 ) - 1 } = 15 , correct to four decimal places.

(Essay)
4.7/5
(40)

If f(x)=5xf ( x ) = 5 ^ { x } , show that f(x+h)f(x)h=5x(5h1h)\frac { f ( x + h ) - f ( x ) } { h } = 5 ^ { x } \left( \frac { 5 ^ { h } - 1 } { h } \right) .

(Essay)
4.8/5
(40)

A radioactive substance decays in such a way that the amount of mass remaining after t days is given by the function m(t)=13e0.015tm ( t ) = 13 e ^ { - 0.015 t } where m(t)m ( t ) is measured in kilograms. Round your answers to three decimal places. a) Find the mass at time t=0t = 0 . b) How much of the mass remains after 100 days?

(Short Answer)
4.7/5
(35)

The age of an ancient artifact can be determined by the amount of radioactive carbon-14 remaining in it. If D0D _ { 0 } is the original amount of carbon-14 and D is the amount remaining, then the artifact's age A (in years) is given by A=8267ln(DD0)A = - 8267 \ln \left( \frac { D } { D _ { 0 } } \right) Find the age of an object if the amount D of carbon-14 that remains in the object is 50% of the original amount D0D _ { 0 } .

(Short Answer)
4.7/5
(32)

Show that log(x+1x)=log(x+1+x)- \log ( \sqrt { x + 1 } - \sqrt { x } ) = \log ( \sqrt { x + 1 } + \sqrt { x } ) . 

(Essay)
4.8/5
(34)

Solve the equation 2x2(3x)5x(3x)+3x+1=02 x ^ { 2 } \left( 3 ^ { x } \right) - 5 x \left( 3 ^ { x } \right) + 3 ^ { x + 1 } = 0 .

(Essay)
4.9/5
(40)

Use the Laws of Logarithms to rewrite the expression log4(x44)\log _ { 4 } \left( \frac { x ^ { 4 } } { 4 } \right) in a form with no logarithm of a product, quotient, root, or powers.  

(Essay)
4.9/5
(39)

If $10,000 is invested at an interest rate of 5% per year, compounded semiannually, find the value of the investment after the given number of years. (a) 5 years (b) 10 years (c) 15 years

(Short Answer)
4.8/5
(31)

The age of an ancient artifact can be determined by the amount of radioactive carbon-14 remaining in it. If D0D _ { 0 } is the original amount of carbon-14 and D is the amount remaining, then the artifact's age A (in years) is given by A=8267ln(DD0)A = - 8267 \ln \left( \frac { D } { D _ { 0 } } \right) Find the age of an object if the amount D of carbon-14 that remains in the object is 85% of the original amount D0D _ { 0 } .

(Short Answer)
4.8/5
(28)

A certain strain of bacteria divides every three hours. If a colony is started with 50 bacteria, then the time t (in hours) required for the colony to grow to N bacteria is given by t=3log(N/50)log2t = 3 \frac { \log ( N / 50 ) } { \log 2 } Find the time required for the colony to grow to five million bacteria.

(Short Answer)
4.8/5
(39)

Find the exponential function whose graph is given. Find the exponential function whose graph is given.

(Essay)
4.9/5
(30)

Rudy wants to invest $1000\$ 1000 in savings certificates that bear an interest rate of 7.5%7.5 \% compounded semiannually. How long will it take for the amount to be $1500?\$ 1500 ?

(Multiple Choice)
4.7/5
(37)

Find the effective yield for an investment that earns 3% per year, compounded quarterly.

(Essay)
4.8/5
(33)

Use the Laws of Logarithms to rewrite log11103\log _ { 11 } \sqrt [ 3 ] { 10 } in a form with no logarithms of products, quotients, or powers.

(Multiple Choice)
4.8/5
(39)

A kettle full of water is brought to a boil in a room with temperature 3232 ^ { \circ } C. After 55 minutes the temperature of the water has decreased from 100100 ^ { \circ } C to 8080 ^ { \circ } C. Find the temperature after another 55 minutes. 

(Essay)
4.9/5
(36)

Use the change of base formula and a calculator to evaluate log63.58\log _ { 6 } 3.58 correct to six decimal places.

(Essay)
4.8/5
(30)
Showing 1 - 20 of 99
close modal

Filters

  • Essay(0)
  • Multiple Choice(0)
  • Short Answer(0)
  • True False(0)
  • Matching(0)