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# Matrices - AS Further Maths HELP! Watch

1. I've attempted a question asking for the matrix of 45 degree rotation anticlockwise about (0,0), and I got root 2 / 2 for cos45 and -root 2 / 2 for sin45....
HOWEVER the answers say that it is 1/root 2
Why is this??? Ended up losing a huge chunk of marks - thank you!
2. type 1/root2 into your calculator
3. (Original post by jcdezoysa)
I know they're both 45, but if I type sin-1(45) I get root2/2 ??
4. (Original post by jjcoolio)
I know they're both 45, but if I type sin-1(45) I get root2/2 ??
root(2)/2 is the exact same number as 1/root(2). The latter is unrationalised however.
5. (Original post by Dapperblook22)
root(2)/2 is the exact same number as 1/root(2). The latter is unrationalised however.
it doesn't work in past paper questions though
6. (Original post by jjcoolio)
it doesn't work in past paper questions though
Both of the numbers will be accepted, as they are exactly the same number.

See attached working if clarification is needed.
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Updated: June 12, 2016
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