If\[\cos \,(\theta -\alpha )=a,\,\,\sin \,(\theta -\beta )=b,\,\,\]the – McqOptions

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1.	If\[\cos \,(\theta -\alpha )=a,\,\,\sin \,(\theta -\beta )=b,\,\,\]then \[{{\cos }^{2}}(\alpha -\beta )+2ab\,\sin \,(\alpha -\beta )\] is equal to
A.	\[4{{a}^{2}}{{b}^{2}}\]
B.	\[{{a}^{2}}-{{b}^{2}}\]
C.	\[{{a}^{2}}+{{b}^{2}}\]
D.	\[-{{a}^{2}}{{b}^{2}}\]
Answer» D. \[-{{a}^{2}}{{b}^{2}}\]

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