We introduce the increasing/decreasing function test, which states we can determine the intervals where a function is increasing and decreasing by finding where its derivative is positive and negative. We solve three examples of using a function's derivative to find where it is increasing and decreasing. #calculus1 #apcalculus Proving the Increasing Decreasing Test: Calculus 1 Course: Calculus 1 Exercises playlist: Join Wrath of Math to get exclusive videos, music, and more: ◉Textbooks I Like◉ Graph Theory: Real Analysis: Abstract Algebra: Linear Algebra: Calculus: Proofs and Set Theory: (available for free online) Statistics: Discrete Math: Number Theory: ★DONATE★ ◆ Support Wrath of Math on Patreon for early access to new videos and other exclusive benefits: ◆ Donate on PayPal: Thanks to Loke Tan, Raül Beienheimer, Matt Venia, Micheline, Doug Walker, Odd Hultberg, Marc, Shlome Ashkenazi, Barbora Sharrock, Mohamad Nossier, Rolf Waefler, Shadow Master, and James Mead for their generous support on Patreon! Outro music is mine. You cannot find it anywhere, for now. Follow Wrath of Math on... ● Instagram: ● Facebook: ● Twitter: My Math Rap channel: