# Tangential & normal acceleration derivations

I'm trying to understand how my book derives the tangential accelration. I drew a picture because it's kind of confusing to explain.

From the triangle we get the tangential and normal components of the velocity.

What my problem is (and I think, and hope, it's something simple that I just can't see) that in the second equation where they find SQ.

They times they take adjacent x sin(angle) = oposite.

but isn't sin = oposite/hypoteneuse ??

shouldn't the formula be adjacent x tan(angle) = opposite = SQ ?

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