It is known that the edge length of regular tetrahedron oabc is equal to 1, m and N are the midpoint of edges OA and BC respectively. Let vector OA = vector a, vector ob = vector B and vector OC = vector C (1) Finding the solution of vector m with respect to base (a, B, c) (2) Finding the length of line segment Mn (1) Finding the solution of the vector Mn with respect to the base (a, B, c) (2) Finding the length of line segment Mn

It is known that the edge length of regular tetrahedron oabc is equal to 1, m and N are the midpoint of edges OA and BC respectively. Let vector OA = vector a, vector ob = vector B and vector OC = vector C (1) Finding the solution of vector m with respect to base (a, B, c) (2) Finding the length of line segment Mn (1) Finding the solution of the vector Mn with respect to the base (a, B, c) (2) Finding the length of line segment Mn

The vector m in the first question doesn't know what it is
The solution of the second problem is as follows: Mn = on-om = 1 / 2 (OC + OB) - 1 / 2oa = 1 / 2 (B + C-A)
Then it can be solved according to the vector formula

Given that the edge length of regular tetrahedron oabc is 1, find: (1) vector OA * vector ob (2) (vector OA + vector OB)

(1) Because it is a tetrahedron, the angle between the two is 60 degrees, and the vector OA * vector ob = 1x1xcos60 = 1 / 2
(2) Let the midpoint of AB be e, (vector OA + vector OB) = 2, vector OE