Hi,
I have three position vectors A=(3,-1,2) B=(-1,-1,-2) C=(3,3,-2) the question says to prove that these three vectors have the same angle I solved it by this law "Cos0 = a.b / |a||b|" and I found the angle between A and B , A and C, B and C as following
for A and B:
A.B = 3(-1)+-1(-1)+2(-2) = -6
|A| = √32 + -12 + 22 = √14
Same for |B|
cos0 = A.B / |A||B| = -6 /√14√6 = -√21 /7 -----> 0 = cos-1(-√21/7)= 130,89°
for A and C = as I did above same steps = 83.456°
for B and C = 150,50°
so my answers aren't match I have asked my teacher he told me to solve it by another way and I couldn't so I am here asking for help. Also I know I have to write it in radian that's not a problem I will convert it at the end
I have three position vectors A=(3,-1,2) B=(-1,-1,-2) C=(3,3,-2) the question says to prove that these three vectors have the same angle I solved it by this law "Cos0 = a.b / |a||b|" and I found the angle between A and B , A and C, B and C as following
for A and B:
A.B = 3(-1)+-1(-1)+2(-2) = -6
|A| = √32 + -12 + 22 = √14
Same for |B|
cos0 = A.B / |A||B| = -6 /√14√6 = -√21 /7 -----> 0 = cos-1(-√21/7)= 130,89°
for A and C = as I did above same steps = 83.456°
for B and C = 150,50°
so my answers aren't match I have asked my teacher he told me to solve it by another way and I couldn't so I am here asking for help. Also I know I have to write it in radian that's not a problem I will convert it at the end