Online Course Discussion Forum

Math Challenge IC Handout 5

 
 
PengChristina的头像
Math Challenge IC Handout 5
PengChristina - 2018年04月4日 Wednesday 01:17
 

I have a few questions. For questions 5.24, can I have a hint for the sequence, I tried finding common differences, but I was at the fourth layer and I couldn't go further. For question 5.27, I'm having trouble understanding the question or the shape and what to do with it. For question 5.28, when I used the method from the lecture, I got different a, b, c values based on the equations I got when I saw it was a quadratic equation and plugged in values.  I know c has to be 5, right?


Thank you!

 
ReynosoDavid的头像
Re: Math Challenge IC Handout 5
ReynosoDavid - 2018年04月10日 Tuesday 10:48
 

When looking at common differences seems to lead nowhere it is also a good idea to look at common ratios as well.

A convex polygon is a polygon where all of its diagonals lie inside of it. Remember, a diagonal is a line segment obtained by joining the vertices of the polygon. The sequence is then the number of diagonals of a polygon of $n$ sides. A triangle has no diagonals, so $d_0 = 0$. A quadrilateral has two diagonals, so $d_4= 2$.

In problem 5.28, note the third differences are not all 0, so  the sequence will not be given by a quadratic function. (Hint: compare with problem 5.8)