00:01
We're asked to find how long it would take for an investment of $1 ,000 to double if it is compounded semi -annually at 8%.
00:09
So our principal amount, p, is $1 ,000.
00:14
We are compounded at 8%, which is 0 .08 to find that we did 8 divided by 100.
00:22
Semi -annually means twice per year, so n will equal 2.
00:26
And our value for a is our final amount.
00:29
In this case, we want our initial investment to double 1 ,000 times 2 is a value of 2000.
00:36
From here, we're going to plug our values for pr, n, and a back into our original equation so that we can calculate time.
00:44
So 2 ,000 equals 1 ,000 times 1 plus 0 .08 divided by 2 ,000 raised to the 2t.
01:09
We're going to start by simplifying within our parentheses.
01:14
So 0 .08 divided by 2 is 0 .04.
01:18
We're going to add 1 to that.
01:20
So inside of our parentheses, we have a base value of 1 .04 raised to the 2t.
01:37
Now, from here, we're going to divide both sides by 1 ,000 so that we can isolate our exponential term.
01:50
2 ,000 divided by 1 ,000 is 2...