Cho góc 0<a<90 rút gọn. A= sin^6a+cos^6a+3sin^2a.cos^2a
cho góc 0<a<90 rút gọn
- a . A= sin^6a+cos^6a+3sin^2a.cos^2a
- b . B=cos^4+2cos^2a.sin^2a+sin^4a
- c . C=sin^4a+cos^2a.sin^2a+cos^2a
- d . D=1/1+sin a + 1/1-sin a - 2 tan^2a
- e . E=2015sin^2 20 +sin40+2015cos^2 20-cos50+tan20 tan 70
- g . G=sin^2 10 +sinsin^2 20 +sin^2 30 +sin^2 80 +sin^2 70 +sin^2 60
- f . F=cos^2 12+cos^2 78 +cos^2 1 +cos^2 89 +cos^2 45