The Leibniz formula for π states that 1−31+51−71.......=4π or 4(1−31+51−71.......)=π. The following procedure uses the Lebniz formula to prove that π=4. Find the incorrect step.
Step 1 - Termwise, add 4(31−51+71.......) to the LHS of the formula, and then subtract it at the end again, to keep the value constant at π. Doing so, we get 4(1+31−31+51−51........)−4(31−51+71.......)=π
Step 2 - We can see that 31−51+71.......=−(4π−1), so 4(1)−(−(4π−1)=π
Step 3 - Simplifying,we get (4−1+4π)=π We subtract 4π from both sides to obtain 3=43π But this means that π=4!