K value = natural log (.5) / half-life
half-life = natural log (.5) / k value
half-life = -.693147 / 0.1011
half-life =
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6.8560534125
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I'd say the k value should be negative AND it should have units.
Answer:

Step-by-step explanation:
To solve this problem you must know the formula of subtraction of angles for the function cosx.
The formula is:

We can write 30° as: 45° - 15°
Then:

Using the formula for subtraction of angles we have:

Notice that we have achieved the expression shown in the statement
Finally:

Answer:
30 %
Step-by-step explanation:
Answer:
$23,360
Step-by-step explanation:
Calculation to determine how much carol originally invested in the account
First step is to divide £23517.60 by 1.025
= (23,517.60)/(1+.025)
= (23,517.60)/1.025
=$22,944
Second step is to add back the $1,000 withdrew
=$22,944+$1,000
=$23,944
Now let calculate how much carol originally invested in the account
$23,944=1.025P
Divide both side by 1.025
P=$23,944/1.025
P=$23,360
Therefore the amount that carol originally invested in the account is $23,360