Question

numero 13!!!!!!!!!!!!!!

Answer 1

Cos 75 =cos (30+45)

cos (a+b) = cos a. cos b - sen a. sen b

cos (30+45) = cos 30 . cos 45 - sen 30 - sen 45

cos (30+45) = \/3/2 . \/2/2 - 1/2 . \/2/2

cos (30+45) = \/6/4 - \/2/4

cos (30+45) = (\/6-\/2)/4

sen 15° =  

Sen (45° - 30°) = sen45° . cos30° - sen30° . cos45° =  

√2/2 . √3/2 - 1/2 . √2/2  

sen 15° = (√6 - √2)/4

tg75=(tag45+tg30)/(1-tg45.tg30) 

tan75=(tag30=(√3/3+1)/(1-√3/3 .1)= ((√3+3)/3)/(3-√3)/3)= 

((√3+3))/(3-√3)= racionalizando, multiplicando por (√3+3) 

fica 

((√3+3))²/((√3+3)(3-√3)=(12+6√3)/( 9-3)=(12+6√3)/6= (2+√3)/1 

tag 75=(12+6√3)/6 ou 

tag75=(2+√3)/1 

=3.732051