7/10 = 0,7
13/10 = 1 целая 3/10 = 1,3
9/10 = 0,9
17/10 = 1 целая 7/10 = 1,7
Возведем в квадрат обе части
(cosx+sinx)²=0
cos²x+2cosxsinx+sin²x=0
(cos²x+sin²x)+sin2x=0
1+sin2x=0
sin2x=-1
2x=arcsin(-1)+2kπ
2x=-π/2+2kπ
x=-π/4+kπ, k∈Z
S(ABCD) = AB*AB
AM = AP = 1/2*AB => MP^2 = (1/2*AB)^2 + (1/2*AB)^2
MP^2 = 1/4*AB^2 + 1/4*AB^2 = 1/2 * AB^2
MP = 1/(корен(2))*АВ
S(MNKP) = MP*MP = 1/2*AB^2 = 1/2*S(ABCD)
S(MNKP) / S(ABCD) = 1/2