Rút gọn biểu thức
\(A=\frac{sin^2\alpha-cos^2\alpha}{1+2sin\alpha.cos\alpha}\)
\(\frac{1-2sin\alpha.cos\alpha}{sin^2\alpha-cos^2\alpha}\)
rút gọn biểu thức trên
rút gọn biểu thức sau:
b, \(\frac{\left(\cos\alpha-\sin\alpha\right)^2-\left(\cos\alpha-\sin^2\alpha\right)}{\cos\alpha.\sin\alpha}\)
c,\(C=\sin^6\alpha+\cos^6\alpha+3\sin^6\alpha.\cos^2\alpha\)
Rút gọn :
\(A=\frac{1+2\sin\alpha\cos\alpha}{\sin\alpha+\cos\alpha}\)
Rút gọn biểu thức sau:
\(\frac{2\cos^2\alpha-1}{\sin\alpha+\cos\alpha}\)
2) Rút gọn
a)\(1-\sin^22\)
b)\(\left(1-\cos\alpha\right)\left(1+\cos\alpha\right)\)
c)\(1+\sin^2\alpha+\cos^2\alpha\)
d)\(\sin\alpha-\sin\alpha.\cos^2\alpha\)
e)\(\sin^2\alpha+\cos^2\alpha+2\sin^2\alpha.\cos^2\alpha\)
f)\(\tan^2\alpha-\sin^2\alpha.\tan^2\alpha\)
g)\(\cos^2\alpha+\tan^2\alpha.\cos^2\alpha\)
h)\(\tan^2\alpha\left(2\cos^2\alpha+\sin^2\alpha-1\right)\)
Rút gọn: \(\frac{2\cos^2\alpha-1}{sin\alpha+\cos\alpha}\)
Cảm ơn người giúp mình !
rút gọn
a)A=\(\frac{1+2cos\alpha.sin\alpha}{cos^2\alpha-sin^2\alpha}\)
b)B=\(\left(1+\cot^2\alpha\right)\left(1-sin^2\alpha\right)\)-\(\left(1+\cot^2\alpha\right)\left(1-\cos^2\alpha\right)\)
c)C=\(\sin^6\alpha+\cos^6\alpha\)+\(3\sin^2\alpha.cos^2\alpha\)
CMR\(\frac{1-2\cos^2\alpha}{1+2\sin\alpha.\cos\alpha}=\frac{\sin\alpha-\cos\alpha}{\sin\alpha+\cos\alpha}\)