Welche reale Funktion ist (e ^ (ix) -e ^ (- ix)) / (dh ^ (ix) + dh ^ (- ix)) gleich?

Welche reale Funktion ist (e ^ (ix) -e ^ (- ix)) / (dh ^ (ix) + dh ^ (- ix)) gleich?
Anonim

Antworten:

#tan (x) #

Erläuterung:

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

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

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

So:

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

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

Und:

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

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

So:

# (e ^ (ix) -e ^ (- ix)) / (dh ^ (ix) + dh ^ (- ix)) = (2i sin (x)) / (2i cos (x)) = sin (x) / cos (x) = tan (x) #