跪求!!! math M/S assignment.. 帮帮忙 >.<

elainehappy

The cubic function is one of the most frequency occurring functions. It is interesting to investigate some properties of a cubic function.

1. Consider a cubic function f(x):ax^3+b , where a and b are real number and a not equal to 0. The shape of the graph of the cubic function depends on the value on the values of a and b.

   c) Investigate the points of intersection of the graphs of f and its tangents. What can u say abt the number of point of intersection.

这个问题有 1a, 1b, 1c.. 但是都是各各的，毫无联系。

我现在的问题是，我不会画tangents出来(in the graphs)..

这个是assignment 来的。lower form6 (2012)第一课, function.

拜托，帮帮我忙 >.<

peaceboy

你还是把问题a,b写出来比较好

elainehappy

...补充....

1a, Investigate the shape of the graph of the cubic function for various value of a for the case b=0. Identify the point of inflexion.

1b, Investigate the shape of the graph if both a and b have the same sign and if a and b have different signs. Identify the point of inflexion in each case.

peaceboy

建议你问你的老师那个tangent是哪一个point的tangent，如果没有指定的话，从你的graph里面画出一个intersect 最多point的tangent和最少point的tangent，然后大概解释when x = 哪里到哪里intersect几个point之类的东西

elainehappy

建议你问你的老师那个tangent是哪一个point的tangent，如果没有指定的话，从你的graph里面画出一个intersec ...
peaceboy 发表于 8-6-2012 02:55 PM

    虽然不懂你说什么....但是谢谢

peaceboy

回复 5# elainehappy

你懂tangent是什么鬼东西来得没有？

elainehappy

回复 6# peaceboy


    這個''鬼東西''我懂啊

peaceboy

回复 7# elainehappy


    所以要找f和他的tangent的intersect point 首先要知道它的tangent说的是在哪一个point的tangent
这个你就要去问老师

elainehappy

那個equation is f(x)=ax^3+b..

a 和 b 要放什麽value都可以..

然後，定了那個equation后，要用geogebra把這個equation畫出來，之後就要弄出tangent的shape...

現在問題是，我不懂這個graph (tangent)的step是什麽...

yesoon

i'm lower 6 student,i also dono hw to do it! u do ady?