IGCSE/GCSE/O & A Level/IB/University Student Forum
		Qualification => Subject Doubts => IGCSE/ GCSE => Math => Topic started by: pedrojosetrujillo on May 16, 2009, 12:55:53 pm
		
			
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				Does anyone knw what the rotation, relfection, shear and stretch matrices are?
			
 
			
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				EASY!!! wt exactly u want??? ;D
cuz for every1 it depends on the position and scale factor if any.
			 
			
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				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.
			
 
			
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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
			 
			
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				Thanks man really aprrecitate it. My teacher couldnt tell me this stuff when i asked him. Anymore i would need to knw?
			
 
			
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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  ;)
			 
			
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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
			 
			
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				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  :)
			 
			
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				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