# Trigonometric identities?

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I need to simplify

tan(x)*√(1-sin⁻²(x))

the only two identities I can use are tan(x)=sin(x)/cos(x) and sin²(x)+cos²(x)=1 (these are the only identities in the specification of the course I’m studying)

How would I get rid of the square root?

tan(x)*√(1-sin⁻²(x))

the only two identities I can use are tan(x)=sin(x)/cos(x) and sin²(x)+cos²(x)=1 (these are the only identities in the specification of the course I’m studying)

How would I get rid of the square root?

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#2

(Original post by

I need to simplify

tan(x)*√(1-sin⁻²(x))

the only two identities I can use are tan(x)=sin(x)/cos(x) and sin²(x)+cos²(x)=1 (these are the only identities in the specification of the course I’m studying)

How would I get rid of the square root?

**annabel_gilmour**)I need to simplify

tan(x)*√(1-sin⁻²(x))

the only two identities I can use are tan(x)=sin(x)/cos(x) and sin²(x)+cos²(x)=1 (these are the only identities in the specification of the course I’m studying)

How would I get rid of the square root?

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#3

**annabel_gilmour**)

I need to simplify

tan(x)*√(1-sin⁻²(x))

the only two identities I can use are tan(x)=sin(x)/cos(x) and sin²(x)+cos²(x)=1 (these are the only identities in the specification of the course I’m studying)

How would I get rid of the square root?

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#4

**annabel_gilmour**)

I need to simplify

tan(x)*√(1-sin⁻²(x))

the only two identities I can use are tan(x)=sin(x)/cos(x) and sin²(x)+cos²(x)=1 (these are the only identities in the specification of the course I’m studying)

How would I get rid of the square root?

So it is tan(x)*(1-sin^-2 (x))^1/2

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(Original post by

Is that expression written correctly, because is negative for real ?

**15Characters...**)Is that expression written correctly, because is negative for real ?

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(Original post by

From the identity sin^2 + cos^2 = 1, you can notice that you will get if you proceed to divide both sides of it by .

**RDKGames**)From the identity sin^2 + cos^2 = 1, you can notice that you will get if you proceed to divide both sides of it by .

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#7

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I don’t know I’ve typed up exactly what the textbook says but it’s a new textbook and I have found some mistakes as I’ve been going along. The answer in the back is sinx...

**annabel_gilmour**)I don’t know I’ve typed up exactly what the textbook says but it’s a new textbook and I have found some mistakes as I’ve been going along. The answer in the back is sinx...

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this is a picture of the textbook - it could be a mistake though?

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#9

(Original post by

this is a picture of the textbook - it could be a mistake though?

**annabel_gilmour**)this is a picture of the textbook - it could be a mistake though?

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in

Shall I just leave this question then?

(Original post by

Well if you write tan x = sin x / cos x and then take the sin x inside the square root (so it becomes a multiplier of sin^2 x you can see that something strange is going on

**davros**)Well if you write tan x = sin x / cos x and then take the sin x inside the square root (so it becomes a multiplier of sin^2 x you can see that something strange is going on

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#11

Is anyone else in your class trying the same exercise?

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(Original post by

To me it just looks like a misprint so yes

Is anyone else in your class trying the same exercise?

**davros**)To me it just looks like a misprint so yes

Is anyone else in your class trying the same exercise?

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