SOLUTION: if secB=-4 and B is in QII, find sin2B. Thank you!

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Question 679215: if secB=-4 and B is in QII, find sin2B. Thank you!
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
if secB=-4 and B is in QII, find sin2B
secB=hypotenuse/adj side=-4/1
cosB=-1/4
opp side=√(4^2-1^2)=√(16-1)=√15
sinB=√15/4
sin2B=2sinBcosB=2*√15/4*(-1/4)=-2√15/16=-√15/8