If a, b, c are three mutually perpendicular vectors of equal magnitude, find the angle between a and a + b + c.
A. \(\cos ^{-1}(1 / \sqrt{3})\)
B. \(\cos ^{-1}(1 / 2 \sqrt{2})\)
C. \(\cos ^{-1}(1 / 3 \sqrt{3})\)
D. \(\cos ^{-1}(1 / 2 \sqrt{3})\)
Answer:A
If a, b, c are three mutually perpendicular vectors of equal magnitude, find the angle between a and a + b + c.
A. \(\cos ^{-1}(1 / \sqrt{3})\) B. \(\cos ^{-1}(1 / 2 \sqrt{2})\) C. \(\cos ^{-1}(1 / 3 \sqrt{3})\) D. \(\cos ^{-1}(1 / 2 \sqrt{3})\)