Answer:
15549 yrs old
Step-by-step explanation:
To find the decay constant r we use the formula
t1/2 = 0.693/r
t1/2 is the half-life 5700
5700 = 0.693/r
r = 0.693/5700 = 0.000122 per sec
For the 15% remaining from an initial value of 100%, time t is calculated from
N = Noe^(-rt)
0.15 = 1e^(-0.000122t)
we take natural log of both sides
Ln 0.15 = Ln e^(-0.000122t)
-1.897 = -0.000122t
t = -1.897/-0.000122 = 15549.18 yrs
Approximately 15549 yrs old
The circle area can be defined as x2 + y2 < 3.46^2.
For point M, x2 + y2 = 13.
Since 3.46^2 is about 12, point M is outside the circle!
It is C
all the other options have positive slopes
For ax2 + bx + c = 0, the value of x is given by: For the Quadratic Formula to work, you must have your equation arranged in the form "(quadratic) = 0". Also, the "2a" in the denominator of the Formula is underneath everything above, not just the square root. And it's a "2a" under there, not just a plain "2".