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# Can some1 explain this? watch

1. How do u get the 2 statements below "we see that"?
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2. The writing above says:

Consider a rotation of the radius vector through a small angle dtheta
3. (Original post by e^x)
The writing above says:

Consider a rotation of the radius vector through a small angle dtheta
when you differentiate a unit vector which is a function of theta, it rotates by pi/2 anticloclockwise
4. (Original post by TeeEm)
when you differentiate a unit vector which is a function of theta, it rotates by pi/2 anticloclockwise
Ah right thanks
5. (Original post by e^x)
Ah right thanks
I think I have a sensible proof somewhere if you give me a while
6. (Original post by TeeEm)
I think I have a sensible proof somewhere if you give me a while
How can I observe that fact from the diagram?
7. (Original post by e^x)
How can I observe that fact from the diagram?
It very difficult from there as your lecturer differentiates the unit vector by "vector differentiation from first principles"
8. (Original post by TeeEm)
I think I have a sensible proof somewhere if you give me a while
(Original post by e^x)
The writing above says:

Consider a rotation of the radius vector through a small angle dtheta
Here is my Notes/Proof

Attached Images

9. (Original post by TeeEm)
Here is my Notes/Proof

Thanks a lot
10. (Original post by e^x)
Thanks a lot
my pleasure

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