Mathématiques du secondaire qualifiant

Calcul trigonométrique (1_8)

Exercice 1 tp

Calculer

a = cos( 23π +15π)
4
b = sin(5π- )
4
Correction
a = cos( 23π +15π) = cos(π- )
4 4
Donc a = -cos = - √(2)
4 2
b = sin( 5π - )
4
= sin(π- )
4
donc b = sin = √(2)
4 2
Exercice 2 tp

Calculer

cos²( +15π) + sin²(3π- )
5 5
Exercice 3 tp

Calculer

a = cos( 27π + π )
2 3
Correction
a = cos( 27π + π )
2 3
= cos( 28π-π + π )
2 3

ou encore

= cos( + 14π + π )
2 3
= cos( + π )
2 3
= cos( π - π )
2 3
donc a = sin π = 1
3 2
Exercice 4 tp

Calculer

a = sin( - π )
2 4
b = cos( + π )
2 3
Correction
a = sin( - π )
2 4
= sin( 4π+π - π )
2 4

ou encore

a = sin( π + 2π - π )
2 4
= sin( π - π )
2 4
donc, a = cos π = √(2)
4 2
b = cos( + π )
2 3

Ou encore

b = cos( 4π+π + π )
2 3
= cos( π + 2π + π )
23
= cos( π + π )
2 3
donc b = -sin π = - √(3)
3 2