Réponse :

Explications étape par étape :

cos²(x) + sin²(x) = 1

sin²(x) = 1 - cos²(x)

sin²(x) = 1 -7/25 = 18/25

sin(x) = √(18/25) = (3√2)/5

sin(x) = (3√2)/5

tan(x) = sin(x)/cos(x)

tan(x) = ((3√2)/5)/((√7)/5) = ((3√2) * 5)/(5√7) = (3√2)/√7

tan(x) = ((3√2)*√7)/7 = (3√14)/7

tan(x) = (3√14)/7