Nếu biết $\displaystyle \frac{{{\sin }^{4}}\alpha }{a}+\frac{{{\cos }^{4}}\alpha }{b}=\frac{1}{a+b}$ thì biểu thức$\displaystyle A=\frac{{{\sin }^{8}}\alpha }{{{a}^{3}}}+\frac{{{\cos }^{8}}\alpha }{{{b}^{3}}}$ bằng
A. $\displaystyle \frac{1}{{{\left( a+b \right)}^{2}}}$
B. $\displaystyle \frac{1}{{{a}^{2}}+{{b}^{2}}}$
C. $\displaystyle \frac{1}{{{\left( a+b \right)}^{3}}}$
D. $\displaystyle \frac{1}{{{a}^{3}}+{{b}^{3}}}$
A. $\displaystyle \frac{1}{{{\left( a+b \right)}^{2}}}$
B. $\displaystyle \frac{1}{{{a}^{2}}+{{b}^{2}}}$
C. $\displaystyle \frac{1}{{{\left( a+b \right)}^{3}}}$
D. $\displaystyle \frac{1}{{{a}^{3}}+{{b}^{3}}}$
Loga
Hóa Học lớp 12
