Answer:
4
Step-by-step explanation
you have 2, so count 2 more
1, <u>2</u>, 3 , <em>4</em>!
Answer:
The expression is y(x) = 2400*(1.12)^x
Step-by-step explanation:
The initial amount is:
y(0) = 2400
After the first month it is:
y(1) = y(0)*(1 + 12/100) = 2400*(1 + 0.12) = 2400*(1.12)
After the second month it is:
y(2) = y(1)*(1.12) = y(0)*(1.12)*(1.12) = y(0)*(1.12)²
After the third month it is:
y(3) = y(2)*(1.12) = y(0)*(1.12)²*(1.12) = y(0)*(1.12)³
After "x" months, we have:
y(x) = y(0)*(1.12)^x
y(x) = 2400*(1.12)^x
Now if
, then both
and
. Adding two positive numbers gives another positive number, so
. Why this is useful will be apparent shortly.
Back to the identity:
Factorizing the left hand side, we have
Now, any number squared will be positive, which means the right hand side is necessarily greater than 0.
We showed earlier that
. So we understand that we have
The only way to multiply a number by a positive number to get yet another positive number is to have the first number also be positive, which means
and from this it follows that
in the provided region.
