Calculus key and difficult points record part integral + trigonometric function integral

Differential and integral calculus Key and difficult points records   see   Differential and integral calculus Key and difficult points records

Knowledge point 1 ：

Topic two ：

I still remember that I missed this minus sign and the following integral sign when I first did it ...

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Knowledge point six ：

Seven knowledge points ：

Knowledge point eight ：

Knowledge point 9 ：