Trig Identities: Sum, Difference, Double Angle

Complete the reciprocal identity: $$\cos\ \theta\ =$$ ​ (a)  

Complete the reciprocal identity: $$\csc\ \theta\ =$$ ​ (a)  

Complete the reciprocal identity: $$\tan\ \theta\ =$$ ​ (a)  

Complete the reciprocal identity: $$\cot\ \theta\ =$$ ​ (a)  

Complete the following sum or difference identity: $$\cos\ A\cos\ B\ +\ \sin\ A\sin\ B=$$ ​ (a)  

Complete the following sum or difference identity: $$\cos\ A\cos\ B\ -\ \sin\ A\sin\ B=$$ ​ (a)  

Complete the following sum or difference identity: $$\sin\ A\cos\ B\ -\ \cos\ A\sin\ B=$$ ​ (a)  

Complete the following sum or difference identity: $$\sin\ A\cos\ B\ +\ \cos\ A\sin\ B=$$ ​ (a)  

Complete the following sum or difference identity: $$\frac{\tan\ A\ +\ \tan\ B}{1-\tan A\tan B}=$$ ​ (a)  

Complete the following sum or difference identity: $$\frac{\tan\ A\ -\ \tan\ B}{1+\tan A\tan B}=$$ ​ (a)