Step-by-step explanation:
given :
2x - 3y = 11
-6x + 8y = 34
find : the solutions of the system by using Cramers Rule.
solutions:
in the matrix 2x2 form =>
[ 2 -3] [x] [11]
=
[-6 8] [ y] [34]
D =
| 2 -3 |
|-6 8 |
= 8×2 - (-3) (-6)
= 16-18 = -2
Dx = | 11 -3 |
| 34 8 |
= 11×8 - (-3) (34)
= 88 + 102
= 190
Dy = | 2 11 |
|-6 34 |
= 2×34 - (-6) (11)
= 68 + 66
= 134
x = Dx/D = 190/-2 = -95
y = Dy/D = 134/-2 = -67
the solutions = {-95, -67}
Answer: half the number?
If you write an equation for it:
Let the number be x
1/2x = x - 1/2x
90 + 20x + 10x = 180
30x = 90
x = 3
Answer:
+120/169 or -120/169
Step-by-step explanation:
- let
![cos^{-1}[\frac{5}{13} ] = \alpha](https://tex.z-dn.net/?f=cos%5E%7B-1%7D%5B%5Cfrac%7B5%7D%7B13%7D%20%20%5D%20%3D%20%5Calpha)
where, alpha is some angle that satisfies the assumed condition.
- so,

[ taking cos to the other side or applying cos on both sides]
- now, substitute this in the given expression
as sin
= 
[by general trigonometry formula:
]
so if
, we can get sin
from the above formula as + or - 12/13
(because, after taking square root on both sides we keep + or -]
- as, sin
![2\beta = 2*sin[\beta ]*cos[\beta ]](https://tex.z-dn.net/?f=2%5Cbeta%20%20%3D%202%2Asin%5B%5Cbeta%20%5D%2Acos%5B%5Cbeta%20%5D)
[by general trigonometry formula]
- here, now
![sin[2\alpha ]=2*(+or- 12/13)*5/13\\](https://tex.z-dn.net/?f=sin%5B2%5Calpha%20%5D%3D2%2A%28%2Bor-%2012%2F13%29%2A5%2F13%5C%5C)
so, the final value can be 120/169 or -120/169.