Solvequill Blog · math · 4 min read · 2 views
Trigonometry identities that actually mean something
A visual way to remember $\sin^2\theta+\cos^2\theta=1$ instead of treating it like a random spell.
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Trig identities feel easier when they are attached to a picture. The unit circle is the picture behind the most common one.
The main idea
On the unit circle, the horizontal coordinate is and the vertical coordinate is . The radius is always .
A short example
By the Pythagorean theorem, the right triangle inside the circle has legs and and hypotenuse .
Check while you solve
- Connect sine to vertical height.
- Connect cosine to horizontal distance.
- Use the identity when squares of sine and cosine appear together.
Turn your own question into an explanation video
Type the question or upload a photo; Solvequill produces a narrated video that walks through the solution step by step.
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