What point does a 90 degree rotation move (0, 1) to?

[kash-k]

I've got a math assignment for uni and I got not idea how to do it. I'm willing to pay 100 usd for someone to do it for me. mail me at irortm@gmail.com if interested, pay via paypal.

 

[Howers]

why don't you show us the assigment first. ie. what kind of math? matrix algebra?

 

[kash-k]

here u go. the assignment in full

 

[Defennder]

How about this, you post your attempt and we guide you along, and you get to save US$100? Plus you get to learn something to sit for your exam. You can't pay someone else to take your paper.

 

[kash-k]

In a perfect world I'd do that but it ain't, so here we are back at square one. I got till 1st of September to get this done, It'll take me longer to understand the question let alone answer it. I'm happy to give a $100 to anyone willing to help

 

[kash-k]

here is about half the assignment, if u can do this easily u can probably do the whole thing.

Question 2 (3.5 marks)
Plot the points A(val1, val2), B(val1, val3) and C(val2, val3) on a piece of grid paper and join
the points to form a right-angled triangle DABC . We wish to carry out the following linear
transformations on the triangle.
· A 90° clockwise rotation, about the origin
· A reflection in the line y = x .
(a) Calculate the 2´ 2 matrix for carrying out the 90° clockwise rotation and apply it to the points
A, B and C to obtain new points A', B' and C ' . Plot these points on the same piece of grid
paper to form the triangle DA'B'C '
(b) Calculate the 2´ 2 matrix for carrying out the reflection in the line y = x and apply it to the
points A', B' and C ' to obtain new points A'', B'' and C '' . Plot these points on the same piece
of grid paper to form the triangle DA''B''C ''

 

[HallsofIvy]

the last thing in the world you want to do is to trick your teacher into thinking you know how to do something when you don't. While someone else may be able to do your homework for you, they can't take the tests for you. A 90 degree rotation about the origin should be very simple. In this case you know that the matris is "two by two" and so must be of the form
$$\left[\begin{array}{cc}a & b \\ c & d\end{array}\right]$$
and you just need to find the four numbers a, b, c, and d.

Mark the point (1, 0) on your grid paper. What point does a 90 degree rotation move that point to? You know that
$$\left[\begin{array}{cc}a & b \\ c & d\end{array}\right]\left[\begin{array}{c}1 \\ 0\end{array}\right]= \left[\begin{array}{c}a \\ c\end{array}\right]$$
Comparing that with the point (1, 0) is rotated to gives you a and b.

Now do the same with (0, 1).