How do you find the exact value of the sin, cos, and tan of the angle -105 degrees?

1 Answer
Jul 30, 2018

Below

Explanation:

#sin(-105)#

#=sin(-60-45)#

#=sin((-60)+(-45))#

#=sin(-60)cos(-45)+cos(-60)sin(-45)#

#=-sqrt3/2timessqrt2/2+1/2times-sqrt2/2#

#=-sqrt6/4-sqrt2/4#

#=(-sqrt6-sqrt2)/4#


#cos(-105)#

#=cos(-60-45)#

#=cos((-60)+(-45))#

#=cos(-60)cos(-45)-sin(-60)sin(-45)#

#=1/2timessqrt2/2-(-sqrt3/2times-sqrt2/2)#

#=sqrt2/4-sqrt6/4#

#=(sqrt2-sqrt6)/4#


#tan(-105)#

#=tan(-60-45)#

#=tan((-60)+(-45))#

#=(tan(-60)+tan(-45))/(1-tan(-60)tan(-45)#

#=(-sqrt3-1)/(1-(-sqrt3)(-1))#

#=(-sqrt3-1)/(1-sqrt3)#

#=(-(sqrt3+1))/(1-sqrt3)#

#=(sqrt3+1)/(sqrt3-1)#