Tentukan nilai integral berikut (yg C aja)

misal u = 1+x²
         du = 2x dx --> dx = du/2x

∫ 3x / √1+x² dx = ∫ 3x/ √u.  du/2x
                         = ³/₂ ∫ 1/√u du
                         = ³/₂ ∫ u⁻¹/² du
            
                        = ³/₂. 2u¹/² + c
                        = 3 u¹/² + c
                        = 3 √u + c
                        = 3 √1+x² + c