Jos tan alpha = x + 1 & tan bita = x-1 Etsi sitten mikä on 2cot (alpha-bita) =?

Jos tan alpha = x + 1 & tan bita = x-1 Etsi sitten mikä on 2cot (alpha-bita) =?
Anonim

Vastaus:

# Rarr2cot (alfa-beeta) = x ^ 2 #

Selitys:

Olettaen että, # tanalpha = x + 1 ja tanbeta = x-1 #.

# Rarr2cot (alfa-beta) #

# = 2 / (tan (alfa-beeta)) = 2 / ((tanalphatanbeta) / (1 + tanalpha * tanbeta)) = 2 (1 + tanalphatanbeta) / (tanalphatanbeta) #

# = 2 (1 + (x + 1) * (x-1)) / ((x + 1) - (x-1)) #

# = 2 (peruuta (1) + x ^ 2cancel (-1)) / (peruuta (x) + 1cancel (-x) + 1 = 2 x ^ 2/2 = x ^ 2 #

Vastaus:

# 2cot (alfa-beeta) = x ^ 2 #

Selitys:

Meillä on # Tanalpha = x + 1 # ja # Tanbeta = x-1 #

Kuten #tan (alfa-beeta) = (tanalphatanbeta) / (1 + tanalphatanbeta) #

# 2cot (alfa-beeta) = 2 / tan (alfa-beeta) = 2 (1 + tanalphatanbeta) / (tanalphatanbeta) #

= # 2 (1 + (x + 1) (x-1)) / (x + 1 (x-1)) #

= # 2 * (1 + x ^ 2-1) / (x + 1-x + 1) #

= # (2x ^ 2) / 2 = x ^ 2 #