-7, - 5,8, - 3 are 24 points -7, - 5,8, - 3 are 24 points The result is 24 or - 24. The more you give, the better. The numerical order cannot be changed.

-7, - 5,8, - 3 are 24 points -7, - 5,8, - 3 are 24 points The result is 24 or - 24. The more you give, the better. The numerical order cannot be changed.

(-7)*(-5)-8+(-3)
(-7)*(-5+8)+(-3)
(-7)*[-(-5)-8]-(-3)

If cos θ / cos θ + sin θ / sin θ = 0, try to judge the sign of sin (COS θ) × cos (sin θ)

From cos θ / cos θ + sin θ / sin θ = 0, we know that cos θ is different from sin θ,
So theta is the second or fourth quadrant,
When theta is the second quadrant angle, - 1

A piece of steel plate, length: 9 meters, width: 2 meters, thickness: 2 cm, how much is the weight?

The volume of steel plate v = 9 * 2 * 0.02 = 0.36 cubic meters, the density of steel plate is ρ, the unit is kg, and the weight of steel plate m is 0.36 ρ, the unit is kg

In triangle ABC, if cos ^ 2 A + cos ^ 2 B + cos ^ 2 C = 1, then the shape of triangle ABC is?

If cos ^ 2 A + cos ^ 2 B + cos ^ 2 C = 1
3- (sin^2 A+ sin ^2 B+ sin ^2 C)=1
sin^2 A+ sin ^2 B+ sin ^2 C=2
And, sin ^ 2C = sin ^ 2A + sin ^ 2b-2sinasinbcosc, (cosine theorem, sine theorem combined)
Then, 2Sin ^ 2A + 2Sin ^ 2b-2sinasinbcosc = 2
Then, 2sinasinbcosc = 2Sin ^ 2A + 2Sin ^ 2b-2
=-cos(2A)-cos2B=-2cos(A+B)cos(A-B)=2cosCcos(A-B)
=2cosC(cosAcosB+sinAsinB)
That is, cosccosacosb = 0, a + B + C = 180 ° and a, B, C are greater than 0 °
At least one of cosa, CoSb and COSC is 0
That is, at least one of a, B and C is 90 degrees
So the triangle ABC is a right angle

The image of the function y = cos & # (2x-3) is shifted 6 units to the left, and the corresponding function of the image is?
Is it an odd function or even function? What's the range

The image of y = cos & # 178; (2x - π / 3) is shifted to the left by π / 6 units
The image of y = cos & # 178; [2 (x + π / 6) - π / 3] = cos & # 178; 2x is obtained
The corresponding function of the obtained image is y = cos & # 178; 2x
∵cos²(-2x)=cos²2x
The function y = cos & # 178; 2x is even
∵-1≤cos2x≤1,∴0≤ cos²2x≤1
That is, the value range of the function is [0,1]
[image translation π / 6 units to the left is to replace x with x + π / 6 in the original formula]

How many tons is a cubic meter of gasoline

You need density

Given m ^ 2 + M-1 = 0, find the value of m ^ 3 + 2m-1997
[tip: m ^ 3 + 2m ^ 2-1997 = (m ^ 3 + m ^ 2-m) + (m ^ 2 + m-1) - 1996]

M ^ 3 + m ^ 2-m = m (m ^ 2 + m-1) = 0, so the formula is - 1996

Is the curvilinear integral of coordinates and Green's formula a double integral? What's the connection between it and the double integral
If it's a double integral, does Green's formula represent area or volume

The curvilinear integral of coordinates is a simple definite integral after parameter substitution, but Green's formula can be converted into double integral solution only when the integrand curve is smooth and enclosed in a closed region, and the integrand function satisfies the first-order partial derivative continuity in this region. That is to say, the curvilinear integral of coordinates is essentially a definite integral to work on variable force, Green's formula is just a tool to transform the surface integral of coordinates into double integral, or it can only be transformed under certain conditions. Double integral definitely represents volume. Once again, Green's formula is only a tool, not volume or area. It is a simplified tool like Gauss Stokes formula, After all, the multiple integral is better than the curve surface integral

The rate of advance between every two adjacent area units is 100, and the rate of advance between two volume units is 1000______ (judge right or wrong)

Because the rate of advance between every two adjacent common area units is 100, and the rate of advance between every two adjacent common volume units is 1000, it is wrong to say that the rate of advance between every two adjacent area units is 100, and the rate of advance between two volume units is 1000

Calculation | 2003 / 1-2002 / 1 | + | 2004 / 1-2003 / 1 | - | 2004 / 1-2002 / 1|

|2003/1-2002/1|+|2004/1-2003/1|-|2004/1-2002/1|=1+1-2=0