Find the maximum, minimum and corresponding x value of the function y = 3-4cos (2x + π / 3), X ∈ [- π / 3, π / 6]

Find the maximum, minimum and corresponding x value of the function y = 3-4cos (2x + π / 3), X ∈ [- π / 3, π / 6]

Y = 3-4cos (2x + π / 3), ∵ x ∈ [- π / 3, π / 6]; 2x ∈ [- 2 π / 3, π / 3]; 2x + π / 3 ∈ [- π / 3, 2 π / 3] when 2x + π / 3 = 0, i.e. x = - π / 6, cos (2x + π / 3) = - 1, y gets the minimum value - 1; when 2x + π / 3 = 2 π / 3, i.e. x = π / 6, cos (2x + π / 3) = - 1 / 2, y gets the maximum value 5

Finding the maximum and minimum of the function y = 3-4sinx-4cosx ^ 2

y=3-4sinx-4(1-sin^2x)
=4sin^2x-4sinx-1
=4(sinx-1/2)^2-2
When SiNx = 1 / 2, Ymin = - 2
When SiNx = - 1, ymax = 7

Fill in 8 numbers 2 ~ 9 in the box of the following formula to make the equation hold

What about the formula?

Let a and B be nonzero matrices of order n, and ab = 0, then the rank of a and B ()
A. There must be one equal to zero, B. all less than NC. One less than N, one equal to nd. All equal to n

If: R (a) = n, then A-1 exists, from ab = 0, B = 0, contradiction, so: R (a) < n, similarly: R (b) < n, so choose: B

Two times of a number is 3.6 more than half of the number. What is the number? The solution of the equation

Let this number be X
2X-X/2=3.6
3X/2=3.6
X=2.4

[simple] how many centimeters is one foot, how many centimeters is one foot, how many feet is one foot?

1 foot = 30.5 cm
1 foot = 33.3333 cm
1 foot = 0.9144 feet

When I read a story book, I read half of the whole book on the first day, three fourths of the rest on the second day, and what percentage of the story book on the third day?

1-1/2-(1/2×3/4)=1/8

Given that 1 / A + 1 / B is equal to 8, then the value of 2A + 3ab-2b of a-2ab-b is?

1 of a + 1 of B is equal to 8, and a + B = 8ab
(1) A = 8ab-b into a-2ab-b = 8ab-b-2ab-b = 6ab-2b, a = 8ab-b into 2A + 3ab-2b = 16ab-2b + 3ab-2b = 19ab-4b, the final answer is 6a-2 / 19a-4, strange answer

The car and the truck started from the two places at the same time and went towards each other. After 1.3 hours, the two cars were still 168 kilometers away. After 2.5 hours, the two cars met on the way, and the distance between the two places was far away
Less kilometers

168 ÷ (2.5-1.3) × 2.5 = 350 km

It is known that a, B and C are trilateral lengths of △ ABC, B and C satisfy (b-2) &# 178; + | C-3 | = 0, and a is the solution of the equation | A-4 | = 2. Find the perimeter of △ ABC and judge the shape

∵ (b-2) &# 178; + | C-3 | = 0 (b-2) &# 178; ≥ 0 | C-3 | ≥ 0 ∵ (b-2) &# 178; = 0 | C-3 | = 0 ∵ B-2 = 0, B = 2c-3 = 0, C = 3 ∵ A is the solution of equation | A-4 | 2 ∵ a = 2 or 62 + 3 ＜ 6 (rounding off) ∵ C Δ ABC = 2 + 3 + 2 = 7 when a = 2