cos60°+sin45°-tan30°
=1/2+√2/2-√3/3
=(3+3√2+2√3)/6
6tan2²30°-√3sin60°-2cos45°=?
=6×(√3/3)²-√3×√3/2-2×√2/2
=6×1/3-3/2-√2
=2-3/2-√2
=1/2-√2
=(1-2√2)/2