what is the coefficent of x square in a polynomial
(1+x)(1-2x)(1+3x)........(1+14x)(1-15x)?

Question

what is the coefficent of x square in a polynomial 
(1+x)(1-2x)(1+3x)........(1+14x)(1-15x)?

anonymous · Answer

hey ash what is ur ans?

ash2326 · Answer

tanu I 'm solving, just a moment

anonymous · Answer

hey ash this ques was asked in delhi school of economics entrance

anonymous · Answer

u are sadly wrong as the options given in the ques are -121,-191,-255,-291

anonymous · Answer

Okay brah? You alternation doesn't keep consistent in how you wrote it. Notice the odds are positive in the beginning and then after the .... they turn the other way around. Poorly posed question because the ...'s are ambiguous.

anonymous · Answer

So of course the product is wrong because its inconsistent.

anonymous · Answer

If you fix the ambiguity for me I'll give you the right answer.

anonymous · Answer

hey sorry u were right .it is(1+2x)(1-3x)

anonymous · Answer

u are correct about the alternate sign thing

anonymous · Answer

Its still the same number. -588

anonymous · Answer

http://www.wolframalpha.com/input/?i=product+%281%2B%28-1%29%5E%28n%29*x*n%29%2Cn%2C1%2C15

anonymous · Answer

hey so what should i do?

anonymous · Answer

okay are u good with concavity and convexity?

anonymous · Answer

Maybe? Idk, try it