Question

Va rog sa ma ajutați, dau coroana :))​

Answer 1

Răspuns:

Explicație pas cu pas:

cos(a -b) = cosa*cosb + sina*sinb

x = arccos1/7,  y = arccos13/14

x -y = arccos1/7 -arccos13/14

cos(x-y) = cos(arccos1/7 -arccos13/14) =

     cos(arccos1/7* cos(arccos13/14) +

   + sin(arccos1/7)*sin(arccos13/14) =

 =1/7*13/14 + √(1-(1/7^2)*√(1 -(13/14)^2) =

= 13/(7*14) +(4√3/7)*(√3√3/14) =

= 13/(7*14) + 36/(7*14) = 49/(7*14) = 1/2

cos(x-y) = 1/2 = cos60

x - y = 60 grade