Question #904ee

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Answer 1 · 2018-01-26T10:22:55

#tan(-210)=tan150=-tan30=-sqrt3/3#

#-210^0" "#is in the second quadrant measuring from the x-axis clockwise.

measuring anticlockwise this is the angle #150^0#

#:.tan(-210)=tan150#

#tan# is negative in the second quadrant

#=>tan150=-tan30#

from the standard angle values

#tan30=sqrt3/3#

we have therefore

#tan(-210)=tan150=-tan30=-sqrt3/3#