WBJEE · Free quiz
No signup needed. Answer 5 real WBJEE questions, get instant scoring and solutions, then unlock full mocks and your weak-topic map for free.
Question 1 of 5
HARDTo prove 1 + 2 + 3 + ... + n = n(n+1)/2 by induction, if the statement is true for n = k, we must show it holds for: