The minimum value of the function y = 3-sin square x-4cosx is

The minimum value of the function y = 3-sin square x-4cosx is

y=2+cos²x-4cosx
=(cosx-2)²-2
When cosx

What is the minimum value of the function y = X-1 in [2,3]?

2

The number of girls is three fifths of the class, so the number of boys is two fifths of the number of girls. Right or wrong?

It must be wrong. If there are five students in the class, then there are three girls and two boys. Boys are two-thirds of girls. Boys are two-fifths of the class, not girls

Calculation: root 1 / 8 + root 18, root 12 + root 1 / 27 - root 1 / 3
Simplification: 5 / radical 5 + radical 5 / 4-1 / 4 radical 80 (radical 12-radical 4 / 3) - 2 (radical 1 / 8-1 / radical 2-radical 18)

Can you apply for Baidu Hi? This can't answer the question
I can't get it

One half of a's payment for a computer is equal to one third of B's payment and three seventh of C's payment. It is known that C has paid 120 yuan more than a
How much is the computer?

Let a pay as X
Party B's payment is 1 / 2x △ 1 / 3 = 3 / 2x
C payment is 1 / 2x △ 1 / 7 = 7 / 2x
Because C pays 120 yuan more than a
7 / 2x - x = 120
X = 48 yuan
The price of this computer is equal to x + 3 / 2x + 7 / 2x = 6x = 6 * 48 = 288 yuan

If you move the decimal point to the right by 2 digits, the number will be increased by 100.98. What is the decimal

Let this number be 1.02, then 100x = x + 100.98, so x = 1.02

The ratio of number a to number B is 3 to 2. The ratio of number B to number C is 6 to 7. What's the ratio of number a to number C

Because number A: number b = 3:2 = (3 × 3): (2 × 3) = 9:6
And number B: number C = 6:7
So number A: number B: number C = 9:6:7
Therefore, a: C = 9:7

The equation Sin & # 178; X + 2sinx + a = 0 must have a solution, then the value range of a is ()

sin²x+2sinx+a=0
0≤(sinx+1)^2=1-a≤4
So - 3 ≤ a ≤ 1

The sum of 4 times of a number and 4 is equal to 120% of 4

4x+4=4×1.2
x=0.2

According to the program shown in Fig. 1, the function image of Y and X is obtained, as shown in Fig. 2. If the point m is any point on the positive half axis of Y axis, the intersection image of PQ ∥ X axis is made through the point m and connected with the points P, Q and OP, OQ. Then the following conclusions are obtained: ① when x ＜ 0, y = 2x, ② the area of △ OPQ is a fixed value. ③ when x ＞ 0, y increases with the increase of X. ④ MQ = 2pm. ⑤ ∠ poq can be equal to 90 °
A. ①②④B. ②④⑤C. ③④⑤D. ②③⑤

① (2) when x < 0, y = - 2x, when x > 0, y = 4x, let P (a, b), q (C, d), then AB = - 2, CD = 4, and the area of △ OPQ is 12 (- a) B + 12CD = 3, which is correct; (3) when x > 0, y decreases with the increase of X, which is incorrect; (4) if P (a, b), q (C, d), then AB = - 2, CD = 4, which is correct; (5) if PM = a, then om = - 2A. Then P02 = PM2 + om2 = A2 + (- 2A) 2 = a 2 + 4a2, QO2 = mq2 + om2 = (2a) 2 + (- 2A) 2 = 4a2 + 4a2, pq2 = PO2 + QO2 = A2 + 4a2 + 4a2 + 4a2 + 4a2 = (3a) 2 = 9A2, it is concluded that A4 = 2 ∵ a has a solution, and ∵ poq = 90 ° may exist, so ⑤ is correct; ② ④ ⑤ is correct, so B is selected