Question

Approximate the following numbers using linear approximations (tangent lines) to appropriate functions:
1) 1.04^10 {4% interest compounded annually for 10 years} and 1.02^15 {2% interest compounded annually for 15 years};
2) cubedroot(127) and 4throot(80);
3) sin1.5, cos0.8, and cos1/2

I'm not sure how to do any of these at all, nor the steps on how to approach this..