The vector `(cosalphacosbeta) hat i+(cosalphas inbeta) hat j+(s inalpha) hat k` is a a. null vector b. unit vector c. constant vector d. none of these

Explanation

To determine the nature of the vector \( \vec{A} = (\cos \alpha \cos \beta) \hat{i} + (\cos \alpha \sin \beta) \hat{j} + (\sin \alpha) \hat{k} \), we need to find its magnitude and analyze the result.

### Step 1: Write down the vector
The given vector can be expressed as:
\[ \vec{A} = (\cos \alpha \cos \beta) \hat{i} + (\cos \alpha \sin \beta) \hat{j} + (\sin \alpha) \hat{k} \]

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