Algebra/Trig Review - Pauls Online Math Notes - Lamar University

Algebra/Trig Review⎛7π⎞ 3 ⎛ 7π⎞ 3From this unit circle we can see that cos⎜⎟ = − and cos⎜− ⎟=−. In⎝ 6 ⎠ 2 ⎝ 6 ⎠ 2this case the cosine function is called an even function and so for ANY angle we havecos − θ = cos θ .( ) ( )⎛ π ⎞12. tan ⎜−⎟⎝ 4 ⎠ and ⎛7π⎞tan ⎜ ⎟⎝ 4 ⎠SolutionHere we should note that 7 π π= 2π− so 7 π π and − are in fact the same angle!4 4 4 4The unit circle for this angle is© 2006 Paul Dawkins 50http://tutorial.math.lamar.edu/terms.aspx