Question

what am i supposed to do on this one
is there a formula that i don't understand?​

Answer 1

Răspuns:

49/50

Explicație pas cu pas:

1/(k*(k+1))=(1/k)-(1/(k+1))

So, 1/(1*2)=1/1 - 1/2

1/(2*3) = 1/2 - 1/3

1/(3*4) = 1/3 - 1/4

........

1/(49*50) = 1/49 - 1/50

Making the telescopic sum and reduce the terms with + and - we get:

S= 1/1 - 1/50 = 49/50