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lubricarret
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Homework Statement
Let T1 be the reflection about the line 2x–5y=0 and T2 be the reflection about the line –4x+3y=0 in the euclidean plane.
(i) The standard matrix of T1 o T2 is: ?
Thus T1 o T2 is a counterclockwise rotation about the origin by an angle of _ radians?
(ii) The standard matrix of T2 o T1 is: ?
Thus T2 o T1 is a counterclockwise rotation about the origin by an angle of _ radians?
Homework Equations
I think these equations are correct...
T(v) = A(v)
Reflection:
A =
[((2(u_1))^2)), (2(u_1)(u_2)))
(2(u_1)(u_2)), ((2(u_2))^2))]
*u being the unit vectors
Rotation counterclockwise:
A =
[cosx -sinx
sinx cosx]
S o T is the matrix Transformation with matrix AB
The Attempt at a Solution
I thought I understood this, but again, I guess I've understood something incorrectly.
For the first question, I got the unit vectors to be:
[(5/sqrt29)], (2/sqrt29)] and [(3/5), (4/5)] for T_1 and T_2 respectively.
I then got the standard matrix A of T_1 to be:
[(21/29) (20/29)
(20/29) (-21/29)]
and the standard matrix B of T_2 to be:
[(-7/25) (24/25)
(24/25) (7/25)]
I then took AB = the dot product of these matrices to get:
[(333/6350) (644/6350)
(-644/6350) (333/6350)]
I did similar for the second part, but I'll spare all the numbers, since I'm messing something up...
Further, how would I go about getting the radians? I know the formula for counterclockwise rotation, but wouldn't know how to come up with the radians of such a number...