Vprašanje # 9e7a0

Vprašanje # 9e7a0
Anonim

Odgovor:

# x = 0,1,77,4,51,2pi #

Pojasnilo:

Najprej bomo uporabili identiteto # tan ^ 2x = sek ^ 2x-1 #

# sec ^ 2x-1 + 4secx = 4 #

# sec ^ 2x + 4secx-5 = 0 #

# a = secx #

# a ^ 2 + 4a-5 = 0 #

# (a-1) (a + 5) = 0 #

# a = 1 ali a = -5 #

# secx = 1 ali secx = -5 #

# cosx = 1 ali -1 / 5 #

# x = arccos (1) = 0 in 2pi #

ali

# x = arccos (-1/5) ~~ 1.77 ^ c ali ~ 4.51 ^ c #