Đáp án:
`A=3sin60^{o}-2cos30^{o}+3tan60^o`
`A=3sin60^o-2sin60^o +3tan60^o`
`A=sin60^{o}+3tan60^o`
`A=sqrt3/2+3*sqrt3`
`A=(6sqrt3+sqrt3)/2`
`A=(7sqrt3)/2`
`B=3-2sin30^o +2cos^2 60^o-3tan^2 45`
`B=3-2*1/2+2*1/4-3.1`
`B=3-3-1+1/2`
`B=-1/2`
`C=cos^2 12^o +cos^2 78^o +cos^2 1^o +cos^2 89^o`
`C=cos^2 12^o +sin^2 12^o +cos^2 1^o +sin^2 1^o`
`C=1+1=2`
`D=sin^2 10^o +sin^2 20^o +....+sin^2 70^o +sin^2 80^o`
`D=(sin^2 10^o +sin^2 80^o)+(sin^2 20^o +sin^2 70^o)+(sin^2 30^o +sin^2 60^o)+(sin^2 40^o +sin^2 50^o)`
`D=(sin^2 10^o +cos^2 10^o)+(sin^2 20^o +cos^2 20^o)+(sin^2 30^o +cos^2 30^o)+(sin^2 40^o +cos^2 40^o)`
`D=1+1+1+1=4`
