if a,b,c are non coplanar unit vectors such that vector triple product of a,b,c is (b+c)/2^1/2. then what is angle between a and b

Question

if a,b,c are non coplanar unit vectors such that vector triple
product of a,b,c is (b+c)/2^1/2 then what is angle between a and
b

Adnan Kagzi · Answer

ax(bxc)=/a c/(b)-/a b/(c) = (b+c)/(2^1/2)
comparing lhs and rhs
a b=-1/(2^1/2)
a and b are unit vectors
hence cosx=-1/sqrt2
x=3pi/4
hope my ans is correct