Pythagorean identity — Algebra II, what it means and where it is taught
sin2θ + cos2θ = 1.
Taught in Algebra II.
Where it is taught
Practise this idea
2 questions in the course bank use Pythagorean identity, in Trigonometric Identities & Equations, Parametric Equations.
Problem 1
If sinθ=0.6, find sin2θ+cos2θ.
Worked answer
1
The Pythagorean identity is always 1
Problem 2
For x=6cos t, y=6sin t, find x2+y2.
Worked answer
36
36(cos2 t+sin2 t) = 36