(LG1 + LG2 + LG4 + LG8 +... + lg1024) * log (base on 2) 10

(LG1 + LG2 + LG4 + LG8 +... + lg1024) * log (base on 2) 10

lg1+lg2+lg4+lg8+...+lg1024
=lg1+lg2+lg2^2+lg2^3+...+lg2^10
=0+lg2+2lg2+3lg2+...+10lg2
=lg2*(1+2+3+…… +10)
=55lg2
Log (base on 2) 10
=lg10/lg2
=1/lg2
So the original formula is 55

A cylindrical steel with a floor area of 12.56 square decimeters and a height of 4.5 decimeters is fused into a cone with a bottom diameter of 6 decimeters. How high is the cone?

According to the meaning: 12.56 * 4.5 / (3.14 * 6 / 2 * 6 / 2) * 3 = 6

（1）2ax-（2a-b）（x+y）（2）3a（a^2+4a+4)-a(a-3)(3a+4)
(3) (a-b) (a ^ 2 + AB + B ^ 2) + B ^ 2 (a + b) - A ^ 3, where a = - 4 / 1, B = 2

Are you sure you're right

The base and height of a triangle are adjacent natural numbers. The base is smaller than the height. The area of a triangle is 15 square centimeters. What are the base and height

If the triangle area is 15cm & sup2;,
Then bottom * height = 30
The base and the height are adjacent natural numbers, and the base is smaller than the height,
Obviously, only 5 * 6 = 30 is satisfied,
So the bottom is 5cm and the height is 6cm

How many odd numbers, how many even numbers, how many prime numbers and how many sum numbers are there from 1 to 20

Odd 1,3,5,7,9,11,13,15,17,19
Even 2,4,6,8,10,12,14,16,18,20
Prime 2,3,5,7,11,13,17,19
Sum number 4,6,8,9,10,12,14,15,16,18,20
1 is neither prime nor sum

Cut out the largest triangle in a trapezoid with an upper bottom of 10 cm, a height of 8 cm and a lower bottom of 12 cm. What is the remaining area in square centimeter

2692093 |: Hello. Whether it is isosceles trapezoid, right angle trapezoid or non right angle non isosceles trapezoid, their diagonals can divide the trapezoid into two triangles

As shown in the figure, a is a point on the circle O whose diameter is BC. Ad is perpendicular to BC at point D. through point B, the tangent line of circle O intersects with the extension line of Ca at point e. g is the midpoint of AD
Connect CG and extend to be at point F, extend AF to CB at point F, extend AF to CB at point P
(1) Verification: BF = EF;
(2) Proof: PA is the tangent of circle o

HI, tired

It is known that ∠ AOB = 80 ° and ∠ AOC = 20 ° and that OM and on divide ∠ AOB and ∠ AOC equally, then the degree of ∠ mon is 0______ ．

∵ - AOB = 80 °, AOC = 20 °, OM and on divide ∵ AOB, ∵ AOC equally, ∵ - AOM = 12 ∵ AOB = 12 × 80 ° = 40 °, Aon = 12 ∵ AOC = 12 × 20 ° = 10 ° respectively. ① as shown in Figure 1, when ∵ AOC is outside ∵ AOB, ∵ mon = ∵ AOM + ∵ AON = 40 ° + 10 ° = 50 °; ② as shown in Figure 2, when ∵ AOC is outside ∵ AOB, ∵ mon = ∵ AOM + ∵ AON = 40 ° + 10 ° = 50

It is known that the diameter of the circle O AB = 12cm, P is the midpoint of ob. If the chord CD is made through P and is at an angle of 30 degrees with AB, what is the length of the chord CD?

Do OE ⊥ CD at point e
∵AB=12
∴OB=6
∵ P is the midpoint of ob
Then OP = 3
∵∠OPC=30°
∴OE=1.5
Connect to OC
∴CE=√（6²-1.5²）
∴CD=2CE=3√15

If the equation AX2 + 2x + 1 = 0 has and only has one negative root, then the value range of a is______ ．

(1) When a = 0, the equation becomes 2x + 1 = 0, then x = - 12, and there is only one negative root, which is consistent with the meaning of the problem; (2) when a < 0, ∵ f (0) = 1 > 0, then the equation has only one negative root, which is consistent with the meaning of the problem; (3) when a > 0, f (0) = 1 > 0, and △ = 4-4a, if △ ≥ 0, the equation has two negative roots