Mathematics
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OpenStudy (anonymous):
Let f(x)=(1+b^2)x^2+bx+1 and let m(b) be the minimum value of f(x).As b varies the range of m(b) is-
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OpenStudy (anonymous):
ans. (0,1]
OpenStudy (anonymous):
remember the vertex formula for finding minimum of this quadratic function
OpenStudy (anonymous):
(-b/2a , -D/4a) ??
OpenStudy (anonymous):
yep
OpenStudy (anonymous):
now u know that m(b)=-D/4a
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OpenStudy (anonymous):
yes
OpenStudy (anonymous):
well find the formula for m(b)
OpenStudy (anonymous):
could you pls solve!
OpenStudy (anonymous):
ok
OpenStudy (anonymous):
??
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OpenStudy (anonymous):
sorry its not (0,1]
OpenStudy (anonymous):
@dpaInc
help
OpenStudy (anonymous):
yes... i'm here.... :)
@shubham.bagrecha, is (0, 1] the answer you got or is that the solution?
OpenStudy (anonymous):
thats solution
OpenStudy (anonymous):
hmmm. i keep getting (3/4, 1].... lemme try again...
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OpenStudy (anonymous):
the vertex of the parabola is given by -b/(2a), so in this problem, the vertex is:
\(\large \frac{-b}{2a}\rightarrow \frac{-b}{2(1+b^2)} \)
OpenStudy (anonymous):
U r Quite right answer is (3/4 ,1]
OpenStudy (anonymous):
go on
OpenStudy (anonymous):
the y-coordinate is f(\(\large \frac{-b}{2(1+b^2)} \)) = \(\large \frac{3}{4}+\frac{1}{4(1+b^2)} \)
OpenStudy (anonymous):
as b varies, \(\large \frac{1}{4(1+b^2)} \) ranges from (0, 1/4]
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OpenStudy (anonymous):
so the m(b) varies in the range (3/4,1]
OpenStudy (anonymous):
yes... but idk why the solution is (0, 1]...:(
OpenStudy (anonymous):
maybe question is f(x)=(1+b^2)x^2+2bx+1 .....
OpenStudy (anonymous):
@shubham.bagrecha
if given function is f(x)=(1+b^2)x^2+bx+1 then answer is (3/4,1] not (0,1]