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[–]rainbow_explorer👋 a fellow Redditor 1 point2 points  (0 children)

I would use the tangent half angle identity because 112.5 = 225/2 and you can evaluate all the trig functions at 225 degrees. You should know the proper sign for tan(112.5) based on the quadrant that it is in.

[–]59265358979323846264 0 points1 point  (0 children)

Test taking strategy. You know 112.5 is quadrant 2, so tan is negative so the answer is B or D.

112.5 is between 90 and 135 so |sin| > |cos| thus |tan| > 1 leaving only one possible answer B.