What is the general solution of the differential equation y '' = cosx?

What is the general solution of the differential equation y '' = cosx?

-cosx+C

How to solve the problem of 4x square - 8x + 1 = 0?

4(x*x - 2x)+1=0
4(x*x - 2x+1)=0
Square of 4 (x-1) = 3
The square of (x-1) = 3 / 4
X = positive and negative root 3 / 2 + 1

Solution equation: 16 ^ x + 12 ^ x = 9 ^ x
X power of 16 + x power of 12 = x power of 9

Divide both sides by 9 ^ X
(16/9)^x+(12/9)^x=1
Let a = (4 / 3) ^ x,
That is, (12 / 9) ^ x = a
(16/9)^x=[(4/3)^x]^2=a^2
a^2+a-1=0
a=(4/3)^x>0
So take the positive solution
a=(-1+√5)/2=(4/3)^x
So x = log (4 / 3) [(- 1 + √ 5) / 2]

In the equal ratio sequence {an}, if a1 + A2 = 2, A3 + A4 = 50, find the value of Q

Let the common ratio of the equal ratio sequence {an} be q, from A3 + A4 = 50, we can get a1q2 + a2q2 = 50, that is, Q2 (a1 + A2) = 50, and a1 + A2 = 2, so Q2 = 25. The solution is q = ± 5

How to do equation 14x = 7

Divide both sides by 14
We get x = 0.5

Min = X1 * log (x1) + x2 * log (x2) + X3 * log (x3); the constraint is X1 + x2 + X3 = 1; why do you report errors in lingo

Min = X1 * @ log (x1) + x2 * @ log (x2) + X3 * @ log (x3);! The function should be preceded by @, and the ending semicolon should be in English;
x1+x2+x3=1;

If we want to make the quadratic + Ma + 1 / 4 of 4A a complete square, then M=
Calculate the second power of [x + 1 / 2] and the second power of [X-1 / 2] to get []
If the second power of [x + y] is 7 and the second power of [X-Y] is 3, then the value of XY is []

If we want to make the quadratic + Ma + 1 / 4 of 4A a complete square, then M = ± 2
The second power of [x + 1 / 2] and the second power of [X-1 / 2] is [x & # 178; - 1 / 4] &# 178;
If the second power of [x + y] is 7 and the second power of [X-Y] is 3, then the value of XY is [10]

Let m and n be two points on the radius op of the ball center O, and NP = Mn = OM, respectively, through N, m and o as perpendicular lines, intercept the ball on the surface of OP to obtain three circles, then the area ratio of these three circles is: ()
A. 3，5，6B. 3，6，8C. 5，7，9D. 5，8，9

Let n, m, o be perpendicular to the surface of OP respectively, and the radius of the three circles be R1, R2, R3, and R, then: R12 = R2 − (23R) 2 = 59r2, R22 = R2 − (13R) 2 = 89r2, R32 = R2 − (23R) 2 = R2 ℅ R12: R22: R32 = 5:8:9 ℅ the area ratio of the three circles is 5, 8, 9, so D is selected

This year, I have four digits in the age cube and six digits in the quartic power. I just use the numbers from 0 to 9

Let the age be x, and first determine the cube as a four digit number range: 10

What is the resistance of national standard copper wire?

One square millimeter in cross section and one meter in length is defined as 0.0172 ohm