I need help on both please

Find the one-sided limit (if it exists). (If the limit is infinite, enter 'co' or '-co', as appropriate. If the limit does not otherwise exist, enter DNE.) 6x 2+ x - 1 lim x - (-1/2) + 8x2- 2x - 3 Submit Answer DETAILS MY NOTES 0/2 Submissions Used Use left and right endpoints and the given number of rectangles to find two approximations of the area of the region between the graph of the function and the x-axis over the given interval. (Round your answers to four decimal places.) f(x) = cos(x), 4 rectangles