Given that cos2x = - 7 / 8, X belongs to (π / 2, π), find the value of sin (x + π / 6) - sin2x Cos2x = 7 / 8 wrong number

Given that cos2x = - 7 / 8, X belongs to (π / 2, π), find the value of sin (x + π / 6) - sin2x Cos2x = 7 / 8 wrong number

Cos2x = 7 / 8, cos2x = 2cosx * cosx-1. X belongs to (π / 2, π), so cosx = '` SiNx = ···································································
When expanding the formula, note that the range of SiNx is > 0

Given sin (x + π / 12), X ∈ (π / 2, π), find sin 2x, cos 2x
sin(x+π/12）=3/5

Sin (x + π / 12) = 3 / 5, cos (x + π / 12) = - 4 / 5sin2 (x + π / 12) = 2Sin (x + π / 12) cos (x + π / 12) = - 24 / 25sin2 (x + π / 12) = sin (2x + π / 6) = √ 3 / 2sin2x + 1 / 2cos2x = - 24 / 25cos2 (x + π / 12) = √ 3 / 2cos2x-1 / 2sin2x = 7 / 25sin2x = cos2x = next

The calculation of X + 1 / 3-x + 1 / 3x needs a detailed process, which can not be simplified

=3/(x+1)-3x/(x+1)
=(3-3x)/(x+1)

How to solve 4 (3x-1) ^ + 1 = 4 (3x-1)?

4(3x-1)²+1=4(3x-1)
[2(3x-1)]²-4(3x-1)+1=0
[2(3x-1)-1]²=0
2(3x-1)-1=0
6x-2-1=0
6x=3
x=0.5

How to solve 3x / 50 + 3x / 70 = 5

Multiply both sides by 350 to get: 360x = 5 * 350 = > x = 165 / 36

How to solve 3x / 70 + 3x / 50 = 5?

Both sides multiply 350 at the same time to simplify

How to solve the problem of 40-3x = 1?

Deformation 3x = 40-1 3x = 39 x = 13

How to solve 2.16-0.3x = 0.06

0.3x=2.16-0.06
0.3x=2.1
X=2.1÷0.3
x=7

X = 2 / 3x + 16, the detailed process is solved by linear equation of one variable and tested

X-2 / 3x = 16
-1 / 2 x = 16
X=-32

(3x + 2) cube = 16 (x-3) cube
How to solve it

(3x + 2) cube = 16 (x-3) cube
(3x + 2) square = [4 (x-3)] square
3x+2=4（x-3）
Or 3x + 2 = - 4 (x-3)
x=14
Or x = 10 / 7