Common Logs
Solving Logs
Exponential form
Log Form
Interest
100

0.6351

-0.1971

100

logx(64+3)

x=4

100

log327= 3

33= 27

100

33=27

log3(27)=3

100

$4,000 is invested at 6% compounded quarterly. What is the total after 8 years?

$6,441.30

200

0.0026

-2.58503

200

log4(0.25)=x

x= -1

200

log416= 2

42= 16

200

25=32

log2(32)=5

200

$1,000 is invested at 9% compounded monthly. What is the total after 9 years?

$2,241.12

300

16,256

4.21101

300

log4(2x-1)= log4(16)

x=17/2

300

log(1/100)= -2

10-2= 1/100

300

83=512

log8(512)= 3

300

$5,000 is invested at 8% compounded continuously for 5 years. What is the total amount?

$7,459.12

400

123.4

2.091315

400

12x=18

x= 1.1632

400

log8(4096)=4

84= 4096

400

5-3= 1/125

log5(1/125)=-3

400

What equation do you use to find the half-life?

y=n(1/2)t/a

a= half life

500

11,397,132,483

10.0568

500

35x=85

x= 0.8088

500

log79(493,039)=3

793= 493039

500

6-4=1/1,296

log6(1/1,296)= -4

500

What formula do you use to find compound interest? What formula is used when finding continuous interest?

Compound:

A= P(1+r/n)nt

Continuous:

A= Pert