Thorsday! The 3rd!

Hallo everybody!
Summary: Today we did a quick warm up that consisted of a whole bunch of common algebra mistakes (which took us a wee bit too long :P). After this we got our quiz from last class back and went over the problems. After we finished with the problems we moved on to a little experiment with ether pad where we had a little chaotic conversation about our worries for unit three (check the links on the blog for our two separate pads). Quickly thereafter we moved onto homework questions.
New Stuff: None to report captain!
Solved Questions:
#27: Half-life of a compound @ 5715 years. After 1000 years, only 2 g are left. Find the initial amount.
y=ae^bt
y=ae^b*0 ------> y=a (y intercept)
2= ae^1000b
a= 2/(e^1000b)
1/2 * a = ae^5715b (cancel a's)
ln(1/2)= 5715b
ln(1/2)/5715=b


#17
2000 = 1000(1 + 0.11/12)^12t
ln2 = ln(1 + 0.11/12)^12t
ln2= 12tln(1+0.11/12)
t=ln2/12(ln(1+ 0.11/12))

2000 = 1000e^0.11t
2=e^0.11t
ln2=0.11t
t=ln2/0.11

#43
a) V = mt+b
b) V = ae^kt
30788=ae^0 => a = 30788
18000 = ae^2k
18000/30788 = e^2k
k= ln(18000/30788)/2

Have a great weekend everyone!
Don't forget TEST MONDAY!!
Next scribe: Nick