1please edit question
the no. of values of the pair (a,b) 4 which
a(x+1)2+b(x2-3x-2)+x+1 is an identity
(a)0
(b)1
(c)2
(d)∞
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9 Answers
62why do u want this edited?
it will be when
a+b=0
and
2a-3b+1=0
These are 2 straight lines...
they will meet at one point.. hence "1"
62being an identity could mean taken as constant for all values.. that is what i did!
62yes this may be possible..
Then being identity means zero...
So you have to also equate the constant term to zero!
And then we wud have 3 equations.. (they can not be simultaneously zero :)
1How can you say being an identity means zero or constant???????????????????????????
isn't the following an identity:
(a+b)2=a2+2ab+b2 ???????????????????
62yes ith i agree
we say that something is an identity if it holds fro all values of x..
that is why when only a function is given.. then being identity can be taken as being equal fro all values of x...
dont go so strongly for a single "word"
IIT questions will be very very specific and clear... the take away from any question should be how to solve it :)
isnt it?