6. Find the highest and the lowest points on the curve x2 + xy + yz = 12 7. If x sinnx = At)dt, where f is continuos function, find f(4) . sint 8. Find dx 2 (1 + u2 du ) dt 9. There is line through the origin that divides the region bounded by the parabola y = x - x2 and the x-axis into two regions with equal area. What is the slope of the line? 10. Find the maximum value of the area of the region under the curve y = 4x - x2 from x = a to x = a + 1, for all a > 0