2cos ^ 2 22.5 - 1 Evaluation

2cos ^ 2 22.5 - 1 Evaluation

2cos ^ 2 22.5 - 1 = cos (22.5 * 2) = cos45 = (radical 2) / 2

0 ° < α < 90 ° and 2cos square α + 7SiN α - 5 = 0
Finding the degree of α

2cos²α+7sinα-5=0
2(1-sin²α)+7sinα-5=0
2sin²α-7sinα+3=0
(2sinα-1)(sinα-3)=0
sinα

What is 1 + 2 + 3 + 4 +. 100

5050
Gauss's first and last terms multiplied by the number of terms, divided by 2

11. When the effective value of I1 + I2 is 10a, the phase difference between I1 and I2 is zero（
Which answer would you like to choose
A.0° B.180° C.90° D.270°

Because I1 + I2 = 10 = 40-30
The direction of I1 and I2 is just opposite, so the phase difference is 180 degrees

Lele competes with her father to climb stairs. When her father climbs to the sixth floor, Lele just climbs to the third floor. At this speed, when her father climbs to the eleventh floor, which floor is Lele on?

The ratio of climbing speed between father and LeLe is (6-1): (3-1) = 5:2, (11-1) △ 5 × 2 + 1 = 4 + 1, = 5 (floor); a: when father climbed to the 11th floor, Lele was on the 5th floor

Who can help me write the factor of 1.2.3.4.5.6.7.8.9.10
There can't be any mistake! Who can write it down

Factor of 1: 1
Factor of 2: 1,2
Factor of 3: 1,3
4: 1,2,4
Factor of 5: 1,5
Factor of 6: 1,2,3,6
The factor of 7 is 1,7
Factor of 8: 1,2,4,8
Factor of 9: 1,3,9
Factor of 10: 1,2,5,10

What does tr (a) mean in linear algebra

The trace tr (a) = a11 + A22 +... + ANN of square matrix A, which is equal to the sum of diagonal elements

There are 48 students in class 61 going for a spring outing. They rent 7 boats. The big boat can take 8 people and the small boat can take 6 people. Each boat is full of people. How many boats do they rent? How many boats do they rent

X large vessels
8X+6*(7-X)=48
8X+42-6X=48
2X=6
X=3
There are three big boats and four small boats

Lim [(4 + e ^ 1 / x) / (1 + e ^ 4 / x) + sin2x / | x |] x - > 0 process

Because X - > 0
When sin2x / | x | does not exist (2 for X - > + 0, and - 2 for X - > - 0)
So there is no limit

It is known that a of B = 1 / 3 and 3a plus 2B = 3 / 2. What are the values of a and B?

A = 1 / 3, B = 1, we can get 3 a = 1 B
That is, B + 2B = 3 / 2
b=2/3X3/1
b=2/1
a=6/1
b=2/3