<p>Precalculus is basically calculus, but they don’t tell you that. In precalculus you will learn how to manipulate all concepts that you will see again to a varying degree in the entire calc series. </p>
<p>I had been attending a quarter system, so the two quarters of precalculus would supplement 4 quarters of calculus, and for that matter matter differential equations and linear algebra. </p>
<p>So precalculus to an extent is optional, because you see everything with more depth in calculus. If you have a really good grasp on trig and algebra -especially when they are used together, you could probably transition to calculus without an issue. Precalculus focuses on combining algebra trig and going over the basics of concepts in calculus so when you actually reach calculus you will be like “oh yeah i remember that kidna” which allows you to learn it way faster than “what the hell is going on.”</p>