a) $sin\alpha$ = $\frac{2}{3}$. Tính A = $\frac{cot\alpha-tan\alpha}{cot\alpha+tan\alpha}$
b) $sin\alpha$ = $\frac{1}{3}$, $90^{o}$ < $\alpha$ < $180^{o}$ Tính A = $\frac{tan\alpha+3cot\alpha+1}{tan\alpha+cot\alpha}$
c) $tan\alpha$ = $\sqrt[]{2}$. Tính A = $\frac{sin\alpha-cos\alpha}{sin^{3}\alpha+3cos^{3}\alpha+2sin\alpha}$
d) $tan\alpha$= 3. Tính A = $\frac{sin^{2}\alpha-5cos^{2}\alpha}{2sin^{2}\alpha+3sin\alpha.cos\alpha+cos^{2}\alpha}$
Loga
Sinh Học lớp 12
