Suppose there is such an a, b, c b, c.
Then: from f( 1)=7/2:
a+b+c=7/2,
a=7/2-b-c
Due to:
f(x)≤2x^2+2x+(3/2)
That is, ax 2+bx+c ≤ 2x 2+2x+(3/2)
It applies to all real numbers x,
There are:
(7/2-b-c-2)x^2+(b-2)x+c-3/2≤0
So:
( 1)7/2-b-c-2=0,b-2=0,c-3/2≤0,
Then: b=2, c=- 1/2, a=2.
X 2+(1/2) ≤ f (x)
x2+( 1/2)≤2x 2+2x- 1/2。
For x, not everything is true.
(2)7/2-b-c-2 & lt; 0,
And delta = (b-2) 2-4 (3/2-b-c) (c-3/2) ≤ 0.
b+ c & gt; 1.5①,
b^2+4bc+4c^2- 10b- 12c+ 13≤0②
x ^ 2+( 1/2)≤f(x)
That is, x2+(1/2) ≤ (7/2-b-c) x2+bx+c.
This holds true for all real numbers x.
There is (5-2b-2c) x 2+2bx+2c- 1 ≥ 0.
Same 5-2b-2c >0,
△=(2b)^2-4(5-2b-2c)(2c- 1)≤0
b+ c & lt; 2.5③,
b^2+4bc+4c^2-2b- 12c+5 ≤0④
Obviously, b=c= 1, and a=3/2 satisfies the above category.