Flip and pair: identity with its value

Exercise and reference answers

Matching pairs

1. A

   cos²x + sin²x

   B

   1

2. A

   1 + tan²x

   B

   sec²x

3. A

   1 + cot²x

   B

   cosec²x

4. A

   sin(−x)

   B

   −sin x

5. A

   cos(−x)

   B

   cos x

Explanation