Converting Log and Exponential Form
Solving Algebraic Log Equations with Log Properties
Expanding/Condensing Logarithms
Evaluating Logs
Continuously Compounding/Half-Life
100

Convert to Exponential Form:


log_2(8)=x


2^x=8

100

Solve for x:


5^(2x)=25

x=1

100

Condense the Logarithms:


log_3(2x)-log_3(5y)


log_3((2x)/(5y))

100

Solve using Logarithms:


log_7(49) = x

x=2

100

The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 7 minutes had elapsed?

 

A=A_0(1/2)^(h/t)

13.2g

200

Convert to Logarithmic Form:


4^y=x


log_4(x)=y


200

Solve for x:


5*2^x=240

log_(2)(48)

200

Completely Expand the Logarithm:


log((2x)/y)

log(2)+log(x)-log(y)

200

Solve Using Logarithms:

log_3(1/27)=

x= -3

200

If Phillip J. Fry left .93 in an account with 2.25% interest compounded yearly, how much would be in the account after 1000 years?

A=P(1+r/n)^(nt)

$4,283,508,450

300

Convert to Exponential Form:


log_(x)(4)=2y

(x)^(2y)=4


300

Solve for x:


3^(2x)=27

x=3/2

300

Condense the Logarithms:(use ln the same as any other log)


2log(3)-2log(x)+4log(y)

log((9y^4)/x^2)

300

Solve by Converting:


log_4(x)=-5

x = 1/1024

300

The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how long would it take for 30g to be left?

 

A=A_0(1/2)^(h/t)

4.2 minutes

400

Convert to Logarithmic Form:


2^(x+4)=y


log_2(y)=x+4

400

Solve for x:


2*3^(x-5)=12

log_(3)(6)+5

400

Condense the Logarithms:


3log(x)+4log(2)-5log(z)-3log(3)

log((16x^3)/(27z^5))

log((2^4x^3)/(3^3z^5))

400

Solve using Logarithms:

 

log_x(1/64) = -2

 x = 8

400

If you put $200 in an account that continuously compounds at 3%, how long would it take for the amount to triple to the nearest year?

A=Pe^(rt)

37 years (36.6)

500

Convert to Exponential Form:


log_(3)(5-z)=4y

(3)^(4y)=5-z

500

Solve for x:


 2^(3x)-7=13

(log_(2)(20))/3

500

Completely Expand the Logarithm:


log_7((3x^6y^7)/(z^5))

log_7(3)+6log_7(x)+7log_7(y)-5log_7(z)

500

Solve using Logarithms:


log_(x+2)(16)=2

x=2

500

A radioactive isotope lost 72% of its mass in 3 years. What is the half-life of the isotope?

1.63 years