Let f: double-struck r4 → double-struck r and c(t): double-struck r → double-struck r4. suppose ∇f(1, 1, π, e6) = (0, 1, 5, −2), c(π) = (1, 1, π, e6), and c'(π) = (19, 11, 0, 1). find d(f ∘ c)/dt when t = π.