Pythagorean Identities

Question 1

What is the Pythagorean identity involving cos²(θ) and sin²(θ)?

Answer 1

cos²(θ) + sin²(θ) = 1

Question 2

What is the Pythagorean identity involving tan²(θ)?

Answer 2

1 + tan²(θ) = sec²(θ)

Question 3

What is the Pythagorean identity involving cot²(θ)?

Answer 3

cot²(θ) + 1 = cosec²(θ)