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Flashcards in Trig identities Deck (15)
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1
Q

Sin(x+y)

A

(Sin x)(cos y) + (cos x)(sin y)

2
Q

Cos(x+y)

A

(Cos x)(cos y) - (sin x)(sin y)

3
Q

Cos(x-y)

A

(Cos x)(cos y) + (sin x)(sin y)

4
Q

Sin(x-y)

A

(Sin x)(cos y) - (cos x)(sin y)

5
Q

Tan x

A

Sin x
/
Cos x

6
Q

Sec x

A

1 / cos x

7
Q

Cot x

A

Cos x
/
Sin x

8
Q

Cosec x

A

1 / sin x

9
Q

Tan(x+y)

A

Sin(x+y)
/
Cos(x+y)

10
Q

Sin(2x)

A

Sin(x+x)

= (sin x)(cos x) + (cos x)(sin x)

= 2(sin x)(cos x)

11
Q

Cos(2x)

A

Cos(x + x)

= (Cos x)(cos x) - (sin x)(sin x)

= (cos^2x) - (sin^2x)

12
Q

(Cos^2x) + (sin^2x)

A

1

13
Q

Cos^2x

A

1 - sin^2x

14
Q

Sin^2x

A

1 - cos^2x

15
Q

Cos(2x)

A

1 - 2(sin^2x)

OR

2(cos^2x) - 1