Sum of internal angles of triangle
Big secret rate
Audio graphics
Talk about chickens and rabbits in the same cage
The mystery of positioning
Second, positive and negative reactions.
Same and different
induction and deduction
Accuracy and error
Change and invariability
Third, think skillfully.
Butterfly on the ellipse
Where is infinity?
Draw line segments with compasses
Pedro's rusty compasses
Contribution of self-taught youth
Fourth, shine on you
Ants in the circle
A point in a triangle.
Great and strange
fixed point
Fifth, the topic is being done.
Mathematics of washing clothes
Brick accumulation problem
If the earth is an empty shell
Underground high-speed train
Sixth, see the micro-knowledge
Pearls and seeds
Tangent line of parabola
Infinitesimal is the ghost of quantity?
Limit concept: rigorous but difficult to understand
Can a derivative be defined without the concept of limit?
A preliminary study on the new definition of derivative
Taylor formula is easy to obtain.
Reflection after success
Parabolic arcuate area
Basic theorem of area fraction