九年级下册数学,求解救. (1)COS60°-COS45°＋tan45°, （2）cos²60°＋sin²45°,

(1)COS60°-COS45°＋tan45°,
=1/2-√2/2+1
=(3-√2)/2
（2）cos²60°＋sin²45°,
=(1/2)²+(√2/2)²
=1/4+2/4
=3/4cos30°-sin45°/sin60°-cos45°，(cos30°-sin45°)/(sin60°-cos45°)=[cos(90°-30°)-sin(90°-45°)]/(sin60°-cos45°)=(sin60°-cos45°)/(sin60°-cos45°)=1（1）sinA=0.753，求角A（2）cosB=0.0832，求∠B(3)tanC=45.8求∠C（1）sinA=0.753，∠A=48.85°或∠A=131.15°（2）cosB=0.0832，∠B=85.23°(3)tanC=45.8∠C=88.75°不谢