Is it correct to deduce the tangent of f(x) = 5x^3 + 5x^2 + x + 1 at x = 0.5 to be y = 9.75x - 1.5? If yes, could you show the workings? I have this software named Graph v4.4 (http://www.padowan.dk), which deduced the tangent above, and, according to my knowledge the tangent would be calculated by d...