Simplifying Using Trig Identities

onesun0000

Junior Member
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Dec 18, 2018
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Hi . I am struggling figuring out if my answer here is right.

LHS is the trig expression. I need to simplify it using trig identities. Please verify if my answer is right. your help would be appreciated. (and i didn't mean to write QED there. sorry)

Trigonometric identity.jpg
 
There are two problems with this.

1) You divided by 1 - cos(x). Thus you have the restriction that \(\displaystyle cos(x) \neq 1\).

2) I'm guessing this is along the lines of a typo: \(\displaystyle \dfrac{1}{sin(x)} = csc(x)\), not sec(x).

Notice the interesting little feature of this. Since csc(0) is undefined, and the only place that cos(x) = 1 is at x = 0, we actually don't need 1). But it's always good to check anyway.

-Dan
 
There are two problems with this.

1) You divided by 1 - cos(x). Thus you have the restriction that \(\displaystyle cos(x) \neq 1\).

2) I'm guessing this is along the lines of a typo: \(\displaystyle \dfrac{1}{sin(x)} = csc(x)\), not sec(x).

Notice the interesting little feature of this. Since csc(0) is undefined, and the only place that cos(x) = 1 is at x = 0, we actually don't need 1). But it's always good to check anyway.

-Dan

oh my gosh. yes. sorry. so is sin (x/2) csc x correct?
 
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