√cos58°≈0.728; cos58°≈0.281.
用计算器
cos58度30分等于0.5225
sin9.5度 =0.1650476 cos58度30''=0.52980 tan52度30'=1.303225 sinA=0.4756则角A=28度25'
sin58*cos37-cos58*sin37=sin58*sin58-sin37*sin37=sin58的平方减去sin37的平方=1.08
sin122=sin(90+32)=-sin32=cos58,sin53=cos37,具体正负号可能不对,学了好几年了忘记公式了,思路应该就是这样,希望能帮到你吧,呵呵
cos58°=cos(π/2-32°)=sin32°, ∴原式=9sin32°-6sin32°+1+sin32°+1=2(5sin32°-3sin32°+1)
cos58°cos13°+sin17°sin13°≈ 0.516337467+0.065769323≈0.582
tan30°=√3/3 cos30°= √3/2 cos45°= √2/2 tan45°=1 cos60°=1/2 tan60°= √3 tan90°无意义 cos90°=0
sin122=sin(180-58)=sin58 sin53=sin(90-37)=cos37 cos58度sin37度+sin122度sin53度 =cos58sin37+sin58cos37 =sin(58+37) =sin95 =sin(90+5) =cos5