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Trigonometric identities
Pythagorean, double-angle and sum identities, verified by simplification.
Identities are equations true for every angle. The Pythagorean identity sin²x + cos²x = 1 is Pythagoras on the unit circle; the double-angle and sum formulas follow from it and rotation. To verify one, simplify the difference of the two sides to zero.
Worked example: simplify sin(x)^2 + cos(x)^2
Simplify sin(x)^2 + cos(x)^2
\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}
Step by step
- \sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}
Start from the expression.
- 1
Simplify.
Reveal the answer
1