"sin^-1(sin330)"
I know the answer is π/6, or 30° but how do you figure this out without a calculator? studying for my final thank you!?
回答 (3)
sin^-1 (sin 330) = -30
sin^-1 (sin x) = x if -90<x<90 (or -pi/2 and pi/2)
if x is outside this range...
work with these rules...
sin x = sin (180 - x)
sin x = sin (360 + x)
-sin x = sin -x
or....
sin 330 = -1/2
sin^-1 (-1/2) = -30
inverse sine undoes the sin function so it leaves you with the angle of 330 so the angle is not pi/6 its -pi/6 .
330 is in the fourth quadrant, the reference angle is 30 from the terminal side CLOCKWISE meaning the angle in negative 30 measured from standard position
if the sin x = 1 you find x by taking the inverse sin , because it UNDOES the function. sin^-1 is the inverse function of sin. so just like every other inverse. f^-1 ( f(x) ) = x
in fact it is not what you you think.....- π / 6 or - 30°......sin 330° < 0...sin 330° = sin ( - 30° )
收錄日期: 2021-04-21 12:00:53
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20150722202144AAwjkzj
檢視 Wayback Machine 備份