Introduction To Derivatives Introduction To Differential Equations?

Introduction to Differential Equations? - introduction to derivatives

Hey, I'm teaching differential equations, and I need a little old, but the manual form quite brilliant, possibly in 1974.

Affirms that the statements should be the following

i) the tangent to a curve at any point P is defined perpendicular to the line OP

ii) The speed at which a rumor spreads through the school depends on the number of people who heard them.

Does it matter? The second question seems almost like a branch of probability theory. Moreover, what is a derivative? I have the rules of the slope of the vertical and looks very similar to the rules of the slope in algebra.

Correct me if I'm wrong, but these equations to calculate the length of a curve on a graph, how to calculate the extent of the zone or in the field of algebra it?

Can someone please tell me what are the differential equations, what are they and why are they important? I also have problems with normal functions, because I have not played, tHEM much, but I'm pretty good in the trigonometric functions with the unit circle. Does that help?

All comments are welcome. Thank you all very much! I appologised all questions, but I'm pretty excited about learning these things.