anylor
Sin² x + cos² x = 1 => cos² x = 1 - sin²x 2) sin x = 0.8 => sin² x =0.64 cos²x = 1 - 0.64 = 0.36 => cosx = racine de 0.36 = 0.6 3) valeur exacte de tan x = sin x / cos x = 0.8 / 0.6 = 8/6 4) si sin x = V3/2 => cos x² = 1 -(V3/2 )² = 1 - 3/4 = 1/4 donc cos x = racine (1/4) = 1/2 tan x = sin x / cos x = ( V3/2) / (1/2) = V3 5) même raisonnement sin²x= 1- cos²x = 1-(3/4) =1/4 sinx = 1 / V2 = V2/ 2 tan x = ( V2/2) / ( V(3/4)) = V6 / 3
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=> cos² x = 1 - sin²x
2) sin x = 0.8 => sin² x =0.64
cos²x = 1 - 0.64 = 0.36
=> cosx = racine de 0.36 = 0.6
3) valeur exacte de tan x = sin x / cos x = 0.8 / 0.6 = 8/6
4) si sin x = V3/2 => cos x² = 1 -(V3/2 )² = 1 - 3/4 = 1/4
donc cos x = racine (1/4) = 1/2
tan x = sin x / cos x = ( V3/2) / (1/2) = V3
5) même raisonnement
sin²x= 1- cos²x
= 1-(3/4) =1/4
sinx = 1 / V2 = V2/ 2
tan x = ( V2/2) / ( V(3/4)) = V6 / 3
j'ai noté V pour racine carrée