1. The cost of producing xunits of stuffed alligator toys isc(x)=0.002x^2+6x+4000. Find the marginal cost at the production level of1000 units.

2.Find the derivative of :8x2/x^10

3.Find the derivative of:6x 4.The graph off(x)=2x^3+9x^2168x+21has two horizontal tangents. One occurs at a negative value ofxand the other at a positive value ofx. What is the negative horizontal tangents, what is the positive horizontal tangent