Decompose an equation into tangential and normal components

calculusderivativesintegrationvectors

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Not sure what this question is asking. I know how to find T and N as shown below:

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My problem is finding the "number". It says to give your answer to three decimal places. But I have no clue how they get a number when given a vector/magnitude. Even if I plug in 2, it would still be a vector/magnitude. For example, it would look like this:
$$\frac{<3,\:4,\:5>}{3}$$

How would I solve this problem? Thanks.

Best Answer

First, just find the vectors $\mathbf{T}(2)$ and $\mathbf{N}(2)$.

They want you to find the scalars $c_1, c_2$ so that $\mathbf{r}(2) = c_1\mathbf{T}(2) + c_2\mathbf{N}(2)$.

As a hint, what happens if you take the dot product of both sides with $\mathbf{T}(2)$, given that $\mathbf{T}(2)$ and $\mathbf{N}(2)$ are perpendicular? Ditto with $\mathbf{N}(2)$?

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