4. The function f(x) has the value f(-1) = 1. The slope of the curve y= f(x) at any point is given by the expression dy -=(2x + 1)(y +1) . dx A. Write an equation for the line tangent to the curve y = f(x) at x=-1. B. Use the tangent line from part A to estimate f(-0.9). C. Use separation of variables to find an explicit or implicit formula for y = f(x) , with no integrals remaining. D. Find lim f(x)