http://www.shelovesmath.com/wp-content/uploads/2012/11/Even-Odd-Neither-Functions-Graphs.png
http://faculty.bucks.edu/taylors/calculus/discon.html
https://www.ixl.com/math/precalculus
http://www.purplemath.com/modules/idents.htm
https://www.mathsisfun.com/geometry/unit-circle.html
https://www.khanacademy.org/math/algebra2/exponential-and-logarithmic-functions
http://regentsprep.org/Regents/math/algtrig/ATT14/formulaprac.htm
http://regentsprep.org/Regents/math/algtrig/ATT1/PracSpecial.htm
http://www.regentsprep.org/regents/math/algtrig/ato1/Pracratpower.htm
http://faculty.bucks.edu/taylors/calculus/discon.html
https://www.ixl.com/math/precalculus
http://www.purplemath.com/modules/idents.htm
https://www.mathsisfun.com/geometry/unit-circle.html
https://www.khanacademy.org/math/algebra2/exponential-and-logarithmic-functions
http://regentsprep.org/Regents/math/algtrig/ATT14/formulaprac.htm
http://regentsprep.org/Regents/math/algtrig/ATT1/PracSpecial.htm
http://www.regentsprep.org/regents/math/algtrig/ato1/Pracratpower.htm