the values of a for which the points A,B,C with the position vectors 2i-j+k, i-3j-5k and ai-3j+k respectively are the vertices of a right angled triangle with C=90 are
the values of a for which the points A,B,C with the position vectors 2i-j+k, i-3j-5k and ai-3j+k respectively are the vertices of a right angled triangle with C=90 are