Question 770441
 wanted to know how do you solve the question:
if cos Ө = -1/3 using trig. identities find the exact value of sin(Ө-pi/2) 
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use sin addition formula:
sin(s-t)=sin s cos t-cos s sin t
sin( Ө-π/2)=sin Ө*cos(π/2)-cos Ө*sin(π/2)
=sin Ө*0-cos Ө*1
=-cos Ө=1/3
sin(Ө-pi/2) =1/3