Author Topic: Maths help  (Read 1687 times)

Offline pedrojosetrujillo

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Maths help
« on: May 16, 2009, 12:55:53 pm »
Does anyone knw what the rotation, relfection, shear and stretch matrices are?

Offline hitham_1221

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Re: Maths help
« Reply #1 on: May 16, 2009, 12:58:20 pm »
EASY!!! wt exactly u want??? ;D
cuz for every1 it depends on the position and scale factor if any.
« Last Edit: May 16, 2009, 01:02:00 pm by hitham_1221 »

Offline pedrojosetrujillo

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Re: Maths help
« Reply #2 on: May 16, 2009, 01:01:25 pm »
Im doing jun 05 paper 4 and it asks me to find the 2x2 matric which represents the transformation that maps x onto q. X onto q is a reflection on the y=-x axis. What would be the the 2x2 i would need? Like the general formula.

Q80BOY

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Re: Maths help
« Reply #3 on: May 16, 2009, 01:02:02 pm »
Im doing jun 05 paper 4 and it asks me to find the 2x2 matric which represents the transformation that maps x onto q. X onto q is a reflection on the y=-x axis. What would be the the 2x2 i would need? Like the general formula.

the matrix for reflection in line y=x is 0 1
                                                  1 0

the matrix for refection in line y=-x is 0 -1
                                                  -1 0

the matrix for clockwise rotation of 90 degrees about the origin is 0 1
                                                                                       -1 0

the matrix for anticlockwise rotation of 90 degrees about the origin is 0 -1
                                                                                             1  0

Offline pedrojosetrujillo

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Re: Maths help
« Reply #4 on: May 16, 2009, 01:03:11 pm »
Thanks man really aprrecitate it. My teacher couldnt tell me this stuff when i asked him. Anymore i would need to knw?

Q80BOY

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Re: Maths help
« Reply #5 on: May 16, 2009, 01:06:21 pm »
Thanks man really aprrecitate it. My teacher couldnt tell me this stuff when i asked him. Anymore i would need to knw?

enlargements, e.g.

enalrgement of scale factor 2 is 2 0
                                           0 2

enlargement of scale factor -2 is -2 0
                                              0 -2

gd luck  ;)

Offline guru007

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Re: Maths help
« Reply #6 on: May 16, 2009, 01:07:23 pm »
Im doing jun 05 paper 4 and it asks me to find the 2x2 matric which represents the transformation that maps x onto q. X onto q is a reflection on the y=-x axis. What would be the the 2x2 i would need? Like the general formula.

the matrix for reflection in line y=x is 0 1
                                                  1 0

the matrix for refection in line y=-x is 0 -1


hey gr8 +rep right away !!

I was stuck with this in the specimen paper 2.
U gave me a sugh of relief really !!!!
                                                  -1 0

the matrix for clockwise rotation of 90 degrees about the origin is 0 1
                                                                                       -1 0

the matrix for anticlockwise rotation of 90 degrees about the origin is 0 -1
                                                                                             1  0


Offline hitham_1221

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Re: Maths help
« Reply #7 on: May 16, 2009, 01:07:47 pm »
u always start with the matrix
{1 0}
{0 1}
then u modify it to fit the transformation
in this case it will become
{0 -1}
{-1 0}
hope u understand  :)

Offline victorfrost

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Re: Maths help
« Reply #8 on: May 16, 2009, 01:12:04 pm »
oh u might also need
strech=k 0 =this is when parallel y axis
          0 1

        =1 0 =this is when parallel to x axis
          k 1