let f(x, y, z) = xy³z² and let c be the curve r(t) = eᵗ ᶜᵒˢ⁽ᵗ² ⁺ ¹⁾, ln(t² + 1), 1/√t² + 1 with 0 ≤ t ≤ 1. compute the line integral of ∇f along c.