2、4/3

3、y= 12x-6

4、y'=-2x*sinx^2

5、dy=- 1/( 1+x^2)dx

6、dy/dx=-y/x

7、 12

8. Decreasing interval (negative infinity,-1); Incremental interval (-1, positive infinity); Minimum value-1/e; Infinite maximum

9. When the side length of a small square is a/ 12, the volume is the largest.

10、2cos2x

1 1, (-1/2)*ln( 1-2x)+C, where c is an arbitrary constant.

12、e- 1

13、0

14、√( 1+x^2)

15、π/2- 1