If the two adjacent sides of two rectangles are represented by vectors ` vec p=5 vec a-3 vec b ; vec q=- vec a-2 vec ba n d vec r=-4 vec a- vec b ; vec s=- vec a+ vec b ,` respectively, then the angel between the vector ` vec x=1/3( vec p+ vec r+ vec s)a n d vec y=1/5( vec r+ vec s)` is `cos^(-1)((19)/(5sqrt(43)))` b. `cos^(-1)((19)/(5sqrt(43)))` c. `picos^(-1)((19)/(5sqrt(43)))` d. cannot be evaluate

Options

A. `cos^(-1) ( (19)/(5sqrt43) )`
B. `cos^(-1) ((19)/(5sqrt43))`
C. `pi cos^(-1) ((19)/(5sqrt43))`
D. cannot be evaluated

Answer

B