Use a calculator to evaluate each of the following:

Question

Given:

(i) \(\mathrm{A}=60^{\circ}\) and \(\mathrm{B}=30^{\circ}\)

(ii) \(\mathrm{A}=110^{\circ}\) and \(\mathrm{B}=50^{\circ}\)

(iii) \(\mathrm{A}=225^{\circ}\) and \(\mathrm{B}=135^{\circ}\)

Use a calculator to evaluate each of the following:

(a) \(\cos (\mathrm{A}-\mathrm{B})\)

(b) \(\cos A-\cos B\)

(c) \(\cos \mathrm{A} \cdot \cos \mathrm{B}+\sin \mathrm{A} \cdot \sin \mathrm{B}\)