Answer to Question #59574 in Calculus for RITA

Question

5. If A=5t^2+tj−t^3k and B=sinti−costj. evaluate d/dt(A⋅B)
(a) (5t^2−1)cost+11tsint
(b) (5t−1)sint+11tcost
(c) −1cost+2tsint
(d) (5t^2−1)sint+11tcost
6 If A=5t^2+tj−t^3k and B=sinti−costj . evaluate d/dt(A×B)
(a) (t^3sint−3t^2cost)i−(t^3cost−3t^2sint)j+(5t^2sint−11tcost−sint)k
(b) (t^2sint−3tcost)i−(t^3cost−3tsint)j+(5sint−11tcost−sint)k
(c) (tsint−3t^2cost)i−(t^3cost−3t^2sint)j+(5t^2cost−11tcost−cost)k
(d) (tcost−3t^2cost)i−(t^3sint−3t^2cost)j+(5t^2cost−11tsint−cost)k
9. Let A=x^2yzi−2xz^3j−xz^2 and B=4zi+yj+4x^2k , find ∂^2/∂x∂y(A×B) at (1,0,-2)
(a) 2i−8j
(b) −4i−8j
(c) −i−3j
(d) 5i−2j