Svar:
At vise
Forklaring:
Svar:
Se venligst beviset nedenfor
Forklaring:
Vi behøver
Derfor,
Svar:
Venligst find a Bevis i Forklaring.
Forklaring:
Vi vil bruge Identitet:
Bevis at: -cot ^ -1 (theta) = cos ^ -1 (theta) / 1 + (theta) ²?
Lad cot ^ (- 1) theta = A derefter rarrcotA = theta rarrtanA = 1 / theta rarrcosA = 1 / secA = 1 / sqrt (1 + tan ^ 2A) = 1 / sqrt (1+ (1 / theta) ^ 2) rarrcosA = 1 / sqrt ((1 + theta ^ 2 / theta ^ 2) = theta / sqrt (1 + theta ^ 2) rarrA = cos ^ (- 1) (theta / (sqrt (1 + theta ^ 2)) ) = cot ^ (- 1) (theta) rarrthereforecot ^ (- 1) (theta) = cos ^ (- 1) (theta / (sqrt (1 + theta ^ 2)))
Bevis at cosec (x / 4) + cosec (x / 2) + cosecx = cot (x / 8) -cotx?
LHS = cosec (x / 4) + cosec (x / 2) + cosecx = cosec (x / 4) + cosec (x / 2) + cosecx + cotx-cotx = cosec (x / 4) + cosec ) + farve (blå) [1 / sinx + cosx / sinx] -cotx = cosec (x / 4) + cosec (x / 2) + farve (blå) [(1 + cosx) / sinx] -cotx = cosec x / 4) + cosec (x / 2) + farve (blå) [(2cos ^ 2 (x / 2)) / (2sin (x / 2) cos (x / 2)) - cotx = cosec 4) + cosec (x / 2) + farve (blå) (cos (x / 2) / sin (x / 2)) - cotx = cosec (x / 4) + farve + cotx (x / 2)) - cotx farve (magenta) "Fremgang på lignende måde som før" = cosec (x / 4) + farve (grøn) barneseng (x / 4) -cotx = barnes
Bevis at Cot 4x (sin 5 x + sin 3 x) = Cot x (sin 5 x - sin 3 x)?
# sin a + sin b = 2 sin ((a + b) / 2) cos ((ab) / 2) sin a - sin b = 2 sin ((ab) / 2) cos ((a + b) / 2 ) Højre side: cot x (sin 5x - sin 3x) = cot x cdot 2 sin ((5x-3x) / 2) cos ((5x + 3x) / 2) = cos x / sin x cdot 2 sin x cos 4x = 2 cos x cos 4x venstre side: barneseng (4x) (sin 5x + sin 3x) = barneseng (4x) cdot 2 sin ((5x + 3x) / 2) cos ((5x-3x) / 2) = {cos 4x} / {sin 4x} cdot 2 sin 4x cos x = 2 cos x cos 4 x De er lige quad sqrt #