化简:sin^2(42°+α)-2tan(25°+α)tan(65°-α)+sin^2(48°-α)-cot^2(990°-α)
问题描述:
化简:sin^2(42°+α)-2tan(25°+α)tan(65°-α)+sin^2(48°-α)-cot^2(990°-α)
答
化简:sin^2(42°+α)-2tan(25°+α)tan(65°-α)+sin^2(48°-α)-cot^2(990°-α)