Step-by-step explanation:
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Answer:
Doesn't have solution.
Step-by-step explanation:
x ≠ 0; x > 0 (I)
x - 5 > 0
x > 5 (II)
![log_6 x + log_6 (x + 5) = 2 \\\ log_6 [x(x + 5)] = 2 \\\ x^2 + 5x = 36 \\\ x^2 + 5x - 36 = 0 \\\ \Delta = 5^2 - 4.1.(- 36) \\\ \Delta = 169 \\\ \sqrt{\Delta} = \pm 13 \\\ x' = \frac{- 5 + 13}{2} \\\\ x' = 4 \\\ x" = \frac{- 5 - 13}{2} \\\\ x" = - 9](https://tex.z-dn.net/?f=log_6%20x%20%2B%20log_6%20%28x%20%2B%205%29%20%3D%202%20%5C%5C%5C%20log_6%20%5Bx%28x%20%2B%205%29%5D%20%3D%202%20%5C%5C%5C%20x%5E2%20%2B%205x%20%3D%2036%20%5C%5C%5C%20x%5E2%20%2B%205x%20-%2036%20%3D%200%20%5C%5C%5C%20%5CDelta%20%3D%205%5E2%20-%204.1.%28-%2036%29%20%5C%5C%5C%20%5CDelta%20%3D%20169%20%5C%5C%5C%20%5Csqrt%7B%5CDelta%7D%20%3D%20%5Cpm%2013%20%5C%5C%5C%20x%27%20%3D%20%5Cfrac%7B-%205%20%2B%2013%7D%7B2%7D%20%5C%5C%5C%5C%20x%27%20%3D%204%20%5C%5C%5C%20x%22%20%3D%20%5Cfrac%7B-%205%20-%2013%7D%7B2%7D%20%5C%5C%5C%5C%20x%22%20%3D%20-%209)
Then, this expression doesn't have solution.
I Hope I've helped you.
Answer:
The answer is B
Step-by-step explanation:
Define
![{x} = \left[\begin{array}{ccc}x_{1}\\x_{2}\end{array}\right]](https://tex.z-dn.net/?f=%7Bx%7D%20%3D%20%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dx_%7B1%7D%5C%5Cx_%7B2%7D%5Cend%7Barray%7D%5Cright%5D%20)
Then
x₁ = cos(t) x₁(0) + sin(t) x₂(0)
x₂ = -sin(t) x₁(0) + cos(t) x₂(0)
Differentiate to obtain
x₁' = -sin(t) x₁(0) + cos(t) x₂(0)
x₂' = -cos(t) x₁(0) - sin(t) x₂(0)
That is,
![\dot{x} = \left[\begin{array}{ccc}-sin(t)&cos(t)\\-cos(t)&-sin(t)\end{array}\right] x(0)](https://tex.z-dn.net/?f=%5Cdot%7Bx%7D%20%3D%20%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-sin%28t%29%26cos%28t%29%5C%5C-cos%28t%29%26-sin%28t%29%5Cend%7Barray%7D%5Cright%5D%20x%280%29)
Note that
![\left[\begin{array}{ccc}0&1\\-1&09\end{array}\right] \left[\begin{array}{ccc}cos(t)&sin(t)\\-sin(t)&cos(t)\end{array}\right] = \left[\begin{array}{ccc}-sin(t)&cos(t)\\-cos(t)&-sin(t)\end{array}\right]](https://tex.z-dn.net/?f=%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0%261%5C%5C-1%2609%5Cend%7Barray%7D%5Cright%5D%20%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dcos%28t%29%26sin%28t%29%5C%5C-sin%28t%29%26cos%28t%29%5Cend%7Barray%7D%5Cright%5D%20%3D%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-sin%28t%29%26cos%28t%29%5C%5C-cos%28t%29%26-sin%28t%29%5Cend%7Barray%7D%5Cright%5D%20)
Therefore