Could someone explain me why
$$2- \frac{1}{k} + \frac{1}{(k+1)^2} = 2- \left(\frac{1}{k} - \frac{1}{(k+1)^2}\right)$$
Why the change of positivity/negativity when there is parenthesis? Might be silly question but want to ask anyway.
simple question about polynomial/algebra equality
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algebra-precalculus
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1This is just distributivity. Try to multiply the right side out. Then you get a $+$, otherwise you would get $-$ which is not the left side. – 2017-01-08
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0Mathjax would really help here as the equation is hard to read. – 2017-01-08
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2$a-(b-c)=a-b+c$ – 2017-01-08
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1Suppose one has 5 apples, and a rogue stoled 3, and the one is given back you by magician. So you'll have 5- 3+1. But one the other hand, this situation is exactly the same as if the rogue had had stolen only 2 apples. In that we could just write 5-(3-1). I wrote this for fun, not for offending.) – 2017-01-08