Staals half
1 gram left
0.3 grams left
half lives are normally written in years
it goes likt this

A=final amount
P=initila amount
t=time elapsed
h=time half life is (same units as time)
let's use days as the units of time
we are given
initial amount=1gram
final amount=0.3gram
time=4 days
so

solve for h

take the ln of both sides


times both sides by h

divide both sides by ln(0.3)

use calculator
h=2.30287
3 sig figs
h=2.303 days
Answer:
C) y = -cos(x) +2
Step-by-step explanation:
The centerline is 2, so 2 is added. That leaves out choices A and B.
There is a minimum (not a maximum) at x=0, so the multiplier is negative, eliminating choice D.
The correct equation is that of C: y = -cos(x) +2.
x^5 is your answer because you add exponents when they are not in separate paretheses.
The ratio is 5:4:7:9. The reason why they didn't write it together is that the bananas are written in different form.