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Gramsci
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Homework Statement
T: R^2-->R2 first rotates points through -3pi/4 radian clockwise and then reflects points through the horizontal x1-axis. Find the standard matrix of T.
Homework Equations
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The Attempt at a Solution
Vector 1 is:
(-1sqrt2
- 1 sqrt2)
before the reflection, and after the reflection it is:
(-1 sqrt 2
1 sqrt 2)
This I knew since we can use:
(cos insert radian
sin radian)
for v1.
But for v2, I have some problems.
If I use:
(-sin insert radian
cos insert radian)
to solve this, my answer doesn't seem to be correct.
My attempt:
v2
(1sqrt 2
1 sqrt 2)
before the reflection, since sin is negative here two negatives equals a plus. Cos is plus as we can see.
After the reflection:
v2
(-1sqrt 2
1 sqrt 2)
this however, isn't the answer. Can anyone please help me? I'm having enormous troubles.
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