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Pre-Algebra Videos 36 videos

ACT Math 3.5 Pre-Algebra
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ACT Math Pre-Algebra: Drill 3, Problem 5. Simplify the expression.

ACT Math 4.5 Pre-Algebra
433 Views

ACT Math: Pre-Algebra Drill 4, Problem 5. If N is divisible by 2 and 3, then what is the remainder when N is divided by 6?

ACT Math 5.3 Pre-Algebra
435 Views

ACT Math: Pre-Algebra Drill 5, Problem 3. Find the remainder.

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ACT Math 5.1 Pre-Algebra 466 Views


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Description:

ACT Math: Pre-Algebra Drill 5, Problem 1. Factoring in depreciation, how much is the car worth?

Language:
English Language

Transcript

00:02

And here is your shmoop de jour.

00:04

Simplified tangents squared alpha over sine squared alpha minus 1

00:10

And here are the potential answers...

00:14

Okay well whenever we see a tangent we can change

00:18

to sine over cosine. Now we have a triple layer fraction cake.

00:23

To get rid of it, we multiply by one over sin squared alpha

00:28

The sines squared alpha cancels out on the top and bottom like this

00:31

which leaves us with one over cosine squared alpha -1

00:36

cosine and secant are inverse functions

00:39

so 1 over cosine squared alpha is the same thing

00:43

as secant squared alpha and the handy dandy trig identity

00:46

1 plus tangent squared alpha equals secant squared alpha

00:49

can be rearranged to become secant squared alpha -1

00:53

equals tangent squared alpha. What do you know? We're left with secant squared alpha

00:57

-1 in our expression

00:59

and we just figured out secant squared alpha -1 equals tangent squared alpha.

01:04

Which is option E.

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