Log
e
Compound Interest
Growth/Decay
Mystery
100

log512= ? 

What is 3?
100

ln(e) =?

What is 1?

100

$4,000 is invested in a savings account that has 3% interest compounded continuously and is left there for 18 years. Find the accumulated amount.

What is $6,864.03?

100

In a lab experiment, there are 4,000 bacteria present initially, and 9,000 are present 2 hours later. What is the initial amount?

What is 4,000?

100

What is ln(1)?

What is zero?

200

Condense the log:  log(5x) + 2log(7y)

What is log(35xy)?

200

 e4x+e-6x=?

What is e-2x?
200

$6,000 is invested in a savings account that has 7% interest compounded semiannually and is left there for 10 years. Find the accumulated amount.

What is $11,938.73?
200
The formula for an exponential growth function is:

What is Q(t) = Q0ekt?

200

Find the derivative of ln[(3x)(4x5+6x2)5]. 

What is [3(4x5+6x2)5+15x(4x5+6x)4(20x4+12x) all over (3x)(4x5+6x2)5?

300

Expand the log:    log(6x4/y7  )

What is 4log(6x) -7log(y)?
300

(e6x-e-x)2=?

What is e12x-2e5x+e-2x?

300

$16,000 is invested in a savings account that has 5% interest compounded semiannually. How long will it take for the account to grow to $18,000?

What is 2.38 years?

300

The formula for an exponential decay function is:

What is Q(t) = Q0e-kt?

300

What is the formula for the rate of change of exponential decay?

What is -kQ(t)?
400
Find the derivative of f(x) = x2ln(5x). 

What is x3+2xln(5x)?

400

Find the derivative of f(x) = xe-5x+8.

What is e-5x+8-5xe-5x+8?

400

$8,000 is invested in a savings account that has 9% interest compounded daily. How long will it take for the account to grow to $20,000?

What is 10.16 years?

400

In a lab experiment, there are 5,000 bacteria present initially, and 8,500 are present 3 hours later. How many bacteria will be present at the end of 5 hours?

What is 12,108 bacteria?

400

The half life of radium is 1600 years. Suppose there is 2000mg of radium initially. How many mg of radium will be present after 400 years?

What is 1681.9mg?

500

Find the derivative of f(x) = ln(6x7+8x4+6x+1).

What is (42x6+32x3+6)/(6x7+8x4+6x+1)?

500

Find the derivative of f(x) = e-9x/ex

What is e-9?

500

$9,500 is invested in a savings account that is compounded continuously and will remain there for 20 years. What interest rate is needed to grow the account to $11,000?

What is 0.73%?

500

In the previous problem, k= 0.1769 and Q(5)=12,108. Find the rate of growth of the population of bacteria after 5 hours.

What is 2,141.9?

500

In the previous problem, k=-0.000433 and Q(400)=1681.9. How fast is the amount of radium decaying after 400 years?

What is -0.727?
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