CTET Solved Paper MCQ - CTET September 2015
is
S = 1-2+3-4+5-6+7-8+...+49-50
S = (1+3+5+7+...+49)+(-2-4-6-....-50)
⇒ Sum of first n odd numbers = n2
Sum of first n even numbers = n(n+1)
∴ S = (25)2 - (25)(26)
S = 625 - 650
S = -25
∴ Additive inverse of (-25) is -(-25) = 25
S = (1+3+5+7+...+49)+(-2-4-6-....-50)
⇒ Sum of first n odd numbers = n2
Sum of first n even numbers = n(n+1)
∴ S = (25)2 - (25)(26)
S = 625 - 650
S = -25
∴ Additive inverse of (-25) is -(-25) = 25
109
The value of 
is
is
, where a = 2, b = 3 and c = 0, is
