Pythagorean trigonometric identity
Noun
Meaning
Pythagorean trigonometric identity (plural Pythagorean trigonometric identities)
(trigonometry) The equality
sin
(
x
)
2
+
cos
(
x
)
2
=
1
{\displaystyle \sin(x)^{2}+\cos(x)^{2}=1}
, holding for all real and complex x, equivalent to the application of the Pythagorean theorem to the unit circle.