2cos^2 22.5 - 1求值

2cos^2 22.5 - 1求值 求值：cos^2 1度+cos^2 2度+…+cos^2 180度=___. 求值：cos^2α-sin^2α cos(3π/2 - π/3),求值 求值:cos(arcsin√3/2)= 求值cos(arcsin3/5+2arctan2) 求值∫dx/(cos^2 x) 求值[1/cos^2(80°)-3/cos^2(10°)]1/cos20° sin(π+π/6)-cos(π+π/4)cos(-π/2)+1求值 求值Cos pai/17 *cos 2pai/17*cos 4pai/17*cos 8pai/17 求值:cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11) 求值：cos(π/11)-cos(2π/11)+cos(3π/11)-cos(4π/11)+cos(5π/11) 求值cos^2a+cos^2(a+120°)+cos^2(a+240°) 求值：cos²A+cos²（2π/3+A)+cos²(2π/3-A) 化简求值cos(π/7)cos(2π/7)cos(4π/7) 求值:cos(2pai/7)+cos(4pai/7)+cos(6pai/7)pai打不出,不好意思 求值：﹙1﹚arc sin﹙sin1﹚ ﹙2﹚arc cos﹙cosπ／12﹚ 求值:(根号3)/2×cos(1/2)-(1/2)×sin(π/2)=?