QR questions...

[msu08]

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tan xdegree = tan (90 – x)degree when



A. x = 0
B. x = -30
C. x = -45
D. x = -60
E. x = -90

answer is C why???

 

[adizzle87]

a) tan0 [0] vs tan 90 [1/0]
b) tan(-30) [-1/rad3] vs tan(120) [-rad3/1]
c) tan(-45) [-1] vs tan(135) [-1]

The key is to know your triangles about your unit circle. Knowing the ASTC pnemonic (All Students Take Calculus) helps with getting the angle and signs right as well.