Sum and Difference Identities Review

Give the exact value of  $\cos\left(201\degree\right)\cos\left(51\degree\right)+\sin\left(201\degree\right)\sin\left(51\degree\right).$  

Give the exact value of  $\tan\left(-255\right).$  

Simplify the expression  $\tan\left(\theta-45\right).$  

Find the exact value of  $\cos\left(255\right).$  

Give the exact value of  $\frac{\tan\left(305\degree\right)+\tan\left(25\degree\right)}{1-\tan\left(305\degree\right)\tan\left(25\degree\right)}$  .

Give the exact value of  $\sin\left(110\degree\right)\cos\left(10\degree\right)+\cos\left(110\degree\right)\sin\left(10\degree\right).$  

Simplify the expression  $\sin\left(\theta-270\degree\right).$  

Give the exact value of  $\sin\left(105\right).$  

Simplify the expression  $\frac{\sin^2\left(\theta\right)+\tan^2\left(\theta\right)+\cos^2\left(\theta\right)}{\csc^2\left(\theta\right)}.$  

Simplify the expression  $\frac{\sin\left(\theta\right)\sec\left(\theta\right)}{\tan\left(\theta\right)}+\sin\left(\theta\right)\csc\left(\theta\right).$