The circle x ^ 2 + y ^ 2 = 4 intersects the X and Y axes with a and B, P is a point in the circle, PA, Po and Pb form an arithmetic sequence, and the PA * vector Pb value range is calculated

The circle x ^ 2 + y ^ 2 = 4 intersects the X and Y axes with a and B, P is a point in the circle, PA, Po and Pb form an arithmetic sequence, and the PA * vector Pb value range is calculated

Circle x ^ 2 + y ^ 2 = 4 intersects X and Y axes at a (2,0), B (0,2), P (rcost, rsint) (0

Observe the following monomials: A, 3A & sup2;, 5A & sup2;, 7a & sup2;, 9A & sup2;, ·, and write the nth formula according to the law you found

The coefficient is 2 * 1-1
2*2-1
2*3-1
……
So it is (2n-1) a & sup2;

In the cube abcd-a1b1c1d1, e and F are the midpoint of AD and ab respectively

(1) EF ∥ plane cb1d1 connects BD ∥ BD ∥ b1d1, e and F are the midpoint of AD and ab respectively ∥ EF is the median line of △ abd ∥ EF ∥ BD ∥ EF ∥ b1d1 and b1d1 [plane cb1d1, EF ᦖ plane cb1d1 ∥ EF ∥ plane cb1d1 (2) plane caa1c1 ⊥ plane cb1d1

The minimum value of y = x2 + 7x + 10x + 1 (x ＞ - 1) is______ ．

∵ x ＞ - 1, ∵ x + 1 ＞ 0. Y = x2 + 7x + 10x + 1 = (x + 1) 2 + 5 (x + 1) + 4x + 1 = (x + 1) + 4x + 1 + 5 ≥ 2 (x + 1) · 4x + 1 + 5 = 9 if and only if x = 1. The minimum value of