실제 함수는 (e ^ (ix) -e ^ (- ix)) / (ie ^ (ix) + ie ^ (- ix))는?

대답:

#tan (x) #

설명:

# e ^ (ix) = cos (x) + sin (x) #

#cos (-x) = cos (x) #

#sin (-x) = -sin (x) #

그래서:

(cos (x) + sin (x)) - (cos (-x) + sin (-x)) #

(cos (x) -i sin (x)) = 2i sin (x) # (cos (x)

과:

(cos (x) + sin (x)) + (cos (-x) + sin (-x)) #

cos (x) -sin (x) = 2 cos (x) + sin (x)

그래서:

(xi) = (2isin (x)) / (2icos (x)) = sin (xi)) / cos (x) = tan (x) #