bonjour,
exo 40 :
1) 0,96 = 96% =96/100 =24/25
2) cos²x+sin²x =1
cos²A = 1-0,96²
cos²A =0,0784
cosA =√0,0784 = 0,28
3)tanA = sinA/cosA
= 0,96/0,28 = 24/7
exo 2 :
1a) sinsIh = h/x
b) tansOh = h/(64+x)
c) h =( x*tan sIh
h = (x+64)*tansOh
3a) on sait que h = x*tan34
. ..................h = (x+64)*tan25
x*tan34 = (x+64)*tan25
x*tan 34= x*tan25+64*tan25
x*tan34-x*tan25 = 64*tan25
x = 64*tan25/(x*tan34-x*tan25)
3b) h= (64*tan25*tan34)/(tan34-tan25)
= (64*0,466*0,674)/(0,674-0,466)
= 20,10/0,208 = 96,63m soit 96,7m
