Question

urgent!!!! Dau coroana!!!!!!!​

Answer 1

Răspuns:

Explicație pas cu pas:

1

1/2+1/6+1/12+.....+1/110=1/1·2+1/2·3+1/3·4+.......+1/10·11=

=1/1-1/2+1/2-1/3+1/3-1/4+..........+1/9-1/10+1/10-1/11=

S=1-1/11=10/11

3

a+b+c=360

b=2a

c=a+60           a+2a+a+60=360            4a=300        a=75°

b=150°

c=135°