f(x)= ax2+1, x≤1=x2+ax+b, x>1 is differentiable at x = 1, then (a, b) = _____
(0, 2)
(2, 0)
(2, 2)
(0, 0)
diff ⇒ cont.
∴ a + 1 = 1 + a + b
b = 0
2a = a + 2
⇒ a = 2