Joyce,
tangent line 就是切线! Tangent line is perpendicular to a radius if
the point is on a circle. The perpendicular line to the tangent line has another name called normal line! Just remember this “a normal line is perpendicular to a tangent line”.
We can draw a tangent line on a point in any curve! This is an important concept in Chapter 3, 4 and 5 about derivatives (dy/dx).
In fact, different point on a curve has different tangent line and hence has different gradient. (tangent=gradient on that particular pt.)
Secant line just an extend to a chord. (a chord has a finite length, a secant line is a long long line.)

哦，tangentline 就是切线，谢谢。

Yes, you are right!

the pic of “tangent to a general curve”.why tangent line is draw like this??can’t understand@@

and secant also blur blur@@

Joyce,

tangent line 就是切线! Tangent line is perpendicular to a radius if

the point is on a circle. The perpendicular line to the tangent line has another name called normal line! Just remember this “a normal line is perpendicular to a tangent line”.

We can draw a tangent line on a point in any curve! This is an important concept in Chapter 3, 4 and 5 about derivatives (dy/dx).

In fact, different point on a curve has different tangent line and hence has different gradient. (tangent=gradient on that particular pt.)

Secant line just an extend to a chord. (a chord has a finite length, a secant line is a long long line.)

ok,thx for explanation.any others questions will be ask in messenger if i still have anything that i dont understand. thx ya!^^

ok,thx for explanation.any others questions will be ask in messenger if i still have anything that i dont understand. thx ya!^^