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A rectangular iron block 7 cm long, 6 cm wide, 4.5 cm high and a square iron block 5 cm long are fused into a large cone. The radius of the bottom of the cone is 5 cm. What is the height of the cone?
7 × 6 × 4.5 = 189 CC, 5 × 5 × 5 = 125 CC, 189 + 125 = 314 CC
5 × 5 × 3.14 = 78.5 square centimeter 314 × 3 △ 78.5 = 12 centimeter answer: height 12 centimeter
Believe me, I'm a math teacher in primary school. I can't make a mistake
If the junction of X1 is better than that of X2, and X1 is bigger than X2, then the third pilot should be in the middle
From the known test range [2,4], the interval length is 2,
Using 0.618 method to select the pilot: X1 = 2 + 0.618 × (4-2) = 3.236, X2 = 2 + 4-3.236 = 2.764,
The result at ∵ X1 is better than that at x2,
Then X3 is 4-0.618 × (4-3.236) = 3.528
Given that the line y = KX + B passes through the point a (- 3,0), and intersects with the line y = - 3x at the point P, O is the origin of the coordinate, s △ OAP = 9, the analytical formula of the line is obtained
Substituting a coordinate into y = KX + B to get: - 3K + B = 0, ①, ∵ a (- 3, 0), that is, OA = 3, s △ OAP = 12oa ·| YP ordinate | = 9, P ordinate is 6 or - 6, substituting y = 6 into y = - 3x to get: x = - 2; substituting y = - 6 into y = - 3x to get: x = 2, that is, P (- 2, 6) or (2, - 6), when p (- 2, 6), substituting y = KX + B to get
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