大学　三角関数の微分4回目／secxtanx他3題

New channel 微分積分入門: title sample judged 'whole' (A dedicated calculus teaching channel with consistent worked-example lectures on derivatives, integrals, and series expa); 1 of 3 sampled transcripts showed teaching, 0 not; every title checked strictly; oEmbed verified.

A 6-minute video from 微分積分入門: “大学　三角関数の微分4回目／secxtanx他3題”.

Video by 微分積分入門, played through YouTube's embedded player.