Cái này thì chắc là phải dùng máy tính cầm tay rồi. Đây là các bước thực hiện trên CASIO fx-570ES PLUS.

Đầu tiên và đương nhiên nhất là phải nhấn "on".

Tiếp theo, chỉnh máy tính về chế độ deg (bằng cách ấn shift + mode (set up), sau đó nhấn phím 3. 

Sau đó ta nhấn shift + cos \(\left(cos^{-1}\right)\) và gõ số \(0,7684\) đằng sau ngoặc "(" .

Cuối cùng nhấn "=" để có kết quả chính bằng A.

Ta bấm máy thấy \(cos^{-1}\left(0,7684\right)=39,78957314...\), vậy \(A=39,78957314...\)

Ta có \(VP=\dfrac{A}{x+1}+\dfrac{Bx+C}{x^2-x+1}=\dfrac{A\left(x^2-x+1\right)+\left(Bx+C\right)\left(x+1\right)}{\left(x+1\right)\left(x^2-x+1\right)}\) \(=\dfrac{Ax^2-Ax+A+Bx^2+Bx+Cx+C}{x^3+1}\) \(=\dfrac{\left(A+B\right)x^2+\left(B+C-A\right)x+\left(A+C\right)}{x^3+1}\)

Như vậy để đẳng thức xảy ra thì \(\dfrac{\left(A+B\right)x^2+\left(B+C-A\right)x+\left(A+C\right)}{x^3+1}=\dfrac{1}{x^3+1}\) hay \(\left(A+B\right)x^2+\left(B+C-A\right)x+\left(A+C\right)=1\)

hay \(\left\{{}\begin{matrix}A+B=0\\B+C-A=0\\A+C=1\end{matrix}\right.\). Giải hệ ra ta tìm được \(\left\{{}\begin{matrix}A=\dfrac{1}{3}\\B=-\dfrac{1}{3}\\C=\dfrac{2}{3}\end{matrix}\right.\)

\(sinA\cdot cos\left(B+C\right)+cosA\cdot sin\left(B+C\right)\)

\(=sinA\cdot cos\left(180^0-A\right)+cosA\cdot sin\left(180^0-A\right)\)

\(=sinA\cdot\left(-cosA\right)+cosA\cdot sinA\)

\(=sinA\left(-cosA+cosA\right)=0\).

The surgeon's job is traditionally most common for men. Surgeons have to perform operations on patients. They also have to make important decisions about patients' health and safety. Besides medical knowledge, surgeons need both physical and mental strength to perform long and tiring operations. In addition, surgeons need to have excellent eyesight and skilful hands. A surgeon works with a team, so he / she needs good teamwork and communication skills. Although it is traditionally seen as a male job, the number of women surgeons is increasing now. Women as mentally strong as men, and they can perform long operations. In summary, women can make great surgeons, and everybody will benefit from having both male and female surgeons.

The surgeon's job is traditionally most common for men. Surgeons have to perform operations on patients. They also have to make important decisions about patients' health and safety. Besides medical knowledge, surgeons need both physical and mental strength to perform long and tiring operations. In addition, surgeons need to have excellent eyesight and skilful hands. A surgeon works with a team, so he / she needs good teamwork and communication skills. Although it is traditionally seen as a male job, the number of women surgeons is increasing now. Women as mentally strong as men, and they can perform long operations. In summary, women can make great surgeons, and everybody will benefit from having both male and female surgeons.