Trig Identities

What does the "co" in cofunction represent?

• common

• complimentary

• complementary

• colinear

Which pairs of angles are complementary?

• $125\degree$ and $235\degree$

• $101\degree$ and $79\degree$

• $33\degree$ and $57\degree$

• $\frac{2\pi}{5}$ and $\frac{8\pi}{5}$

 $\cos\left(28\degree\right)=\sin\left(62\degree\right)$  
What identity proves these are equal?

• Pythagorean

• Cofunction

• Reciprocal

• Periodicity

 $\sec\left(120\degree\right)=\sec\left(480\degree\right)$  
What identity proves these are equal?

• Quotient

• Reciprocal

• Cofunction

• Periodicity

 $\tan\left(-\frac{\pi}{4}\right)=-\tan\left(\frac{\pi}{4}\right)$  
What identity proves these are equal?

• Odd symmetry

• Even symmetry

• Periodicity

• Reciprocal

Which of the following is NOT a Pythagorean Identity?

• $\sin^2\left(\theta\right)+\cos^2\left(\theta\right)=1$

• $\tan^2\left(\theta\right)+1=\sec^2\left(\theta\right)$

• $\sec^2\left(\theta\right)+\csc^2\left(\theta\right)=1$

• $1+\cot^2\left(\theta\right)=\csc^2\left(\theta\right)$

 $\cot\left(\frac{\pi}{3}\right)=\cot\left(\frac{4\pi}{3}\right)$  
What identity proves these are equal?

• Cofunction

• Odd symmetry

• Even symmetry

• Periodicity

 $\cos\left(\frac{\pi}{5}\right)=\frac{1}{\sec\left(\frac{\pi}{5}\right)}$  
What identity proves these are equal?

• Reciprocal

• Quotient

• Cofunction

• Even symmetry

 $\cot\left(341\degree\right)=\frac{\cos\left(341\degree\right)}{\sin\left(341\degree\right)}$  
What identity proves these are equal?

• Reciprocal

• Quotient

• Cofunction

• Periodicity

Which of these is true because of a cofunction identity?

• $\sin\left(25\degree\right)=\cos\left(25\degree\right)$

• $\sin^2\left(\frac{3\pi}{4}\right)+\cos^2\left(\frac{3\pi}{4}\right)=1$

• $\tan\left(8\degree\right)=\cot\left(82\degree\right)$

• $\tan\left(15\degree\right)=\frac{1}{\cot\left(15\degree\right)}$