 Solution

ID: past-exam-of-the-mathematics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2011/paper-1/15/a/solution

a \times (b \times c) = (a \cdot c) b - (a \cdot b) c .

It is the requested linear combination of

b

and

c

. The notation

\land

in this question denotes the three-dimensional cross product.

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