Ratkaise (2 + sqrt3) cos theta = 1-sin-teeta?

Vastaus:

# Rarrx = (6n-1) * (pi / 3) #

# Rarrx = (4n + 1) pi / 2 # Missä # NrarrZ #

Selitys:

#rarr (2 + sqrt (3)) cosx = 1-sinx #

# Rarrtan75 ^ @ * cosx + sinx = 1 #

#rarr (sin75 ^ @ * cosx) / (cos75 ^ @) + sinx = 1 #

# Rarrsinx * cos75 ^ @ + cosx * sin75 ^ @ = cos75 ^ @ = sin (90 ^ @ - 15 ^ @) = sin15 ^ @ #

#rarrsin (x + 75 ^ @) - sin15 ^ @ = 0 #

# Rarr2sin ((x + 75 ^ @ - 15 ^ @) / 2) cos ((x + 75 ^ @ + 15 ^ @) / 2) = 0 #

#rarrsin ((x + 60 ^ @) / 2) * cos ((x + 90 ^ @) / 2) = 0 #

Jompikumpi #rarrsin ((x + 60 ^ @) / 2) = 0 #

#rarr (x + 60 ^ @) / 2 = npi #

# Rarrx = 2npi-60 ^ @ = 2npi-pi / 3 = (6n-1) * (pi / 3) #

tai, #cos ((x + 90 ^ @) / 2) = 0 #

#rarr (x + 90 ^ @) / 2 = (2n + 1) pi / 2 #

# Rarrx = 2 * (2n + 1) pi / 2-pi / 2 = (4n + 1) pi / 2 #

Vastaus:

Jos, # Costheta = 0 => sintheta = 1 => theta = (4k + 1) pi / 2, Kinz #

# Theta = 2kpi-pi / 3, Kinz #,

Selitys:

# (2 + sqrt3) costheta = 1-sintheta #

#andcostheta! = 0 #, jakamalla molemmat puolet # Costheta #

# 2 + sqrt3 = sekteta-tanteta => sektheta-tanteta = 2 + sqrt3 - (I) #

#:. 1 / (sectheta-tantheta) = 1 / (2 + sqrt3) ## => (S ^ 2theta-tan ^ 2theta) / (sectheta-tantheta) = 1 / (2 + sqrt3) * (2-sqrt3) / (2-sqrt3) #

# => sektiheta + tanteta = 2-sqrt3 - (II) #

lisääminen # (I) ja (II) #,saamme.# 2sectheta = 4 => sectheta = 2 #

#COLOR (punainen) (costheta = 1/2> 0) #, Mistä annettu equn.

# Costheta = 1/2 => (2 + sqrt3) (1/2) = 1-sintheta ## => 1 + sqrt (3) / 2 = 1-sintheta => väri (punainen) (sintheta = -sqrt (3) / 2 <0) #

# Theta = 2kpi-pi / 3, Kinz #,………. # (IV ^ (th) #neljänneksessä)