ShmoopTube
Where Monty Python meets your 10th grade teacher.
Search Thousands of Shmoop Videos
Series Videos 1 videos
ACT Math: Pre-Algebra Drill 4, Problem 2. What is the fourth term in the series?
ACT Math 4.2 Pre-Algebra 390 Views
Share It!
Description:
ACT Math: Pre-Algebra Drill 4, Problem 2. What is the fourth term in the series?
Transcript
- 00:03
It's howdy-shmoopy time... It's howdy-shmoopy time...
- 00:07
The first term in a series is the square root of x.
- 00:10
Each subsequent term is determined as the
- 00:12
previous term raised to the power of three-halves. What is the fourth term?
- 00:16
And here are the potential answers...
Full Transcript
- 00:22
Ugh. This one is... ugly. But maybe it's
- 00:25
pretty on the inside. Let's think this one through.
- 00:28
In any question where we have both a fraction AND a square root sign, odds are good that
- 00:33
they are testing us on whether or not we realize that a square root is just the inside part
- 00:37
raised to the one half power.
- 00:40
That is, the square root of x here is the same as x to the one half.
- 00:44
So... now that we are all living in Exponentland...
- 00:47
We have a series of 4 terms... and term 1 here is x to the one half.
- 00:52
Now we raise the power to three-halves for the second term -- and we know -- hopefully
- 00:57
-- that if we are raising exponents to powers we just multiply the exponents...
- 01:01
...so in this case we multiply one half by three halves to get x to the three-fourths
- 01:06
as the second term.
- 01:08
Now do it again to get the 3rd term.
- 01:10
We have x to the three-fourths to the power 3 over 2, which is multiplied to get 3/4 times
- 01:16
three-halves, or 9/8.
- 01:18
Almost to the promised land... located conveniently between Exponentland and Frontierland...
- 01:24
Ok... we have x to the 9/8 to the three-halves, so we multiply 9 over 8 by 3 over 2 to get
- 01:33
27 over 16... or x to the 27/16ths... and the answer is E.
- 01:40
As in, "Exponentland."
Related Videos
ACT Math: Intermediate Algebra: Drill 3, Problem 1. Find the fifth number in the series.
ACT Math: Plane Geometry Drill 3, Problem 1. What is the area of the trapezoid shape in the video?
ACT Math: Coordinate Geometry Drill 1, Problem 1. Which inequality is expressed by the number line?
We don't like knocking people down to size, but we do like simplifying radicals. Join us?
If fleeing criminals always fled the scene of the crime at perfect right angles, it would be much easier to determine their whereabouts. Fortunatel...