课本是同学们学习的根本,对课本例、习题进行多角度的思考,既可培养同学们对数学的兴趣,也能提高同学们的思维能力和解题能力.有这样一道课本习题:(普通高中课程标准实验教科书人教A版数学必修2P67练习第1题)如图1,在三棱锥V-ABC中,VA=VC,AB=BC,求证:VB⊥AC. Textbooks are the basis for students to learn, textbook cases, exercises a multi-angle thinking, not only can cultivate students’ interest in mathematics, but also can improve their thinking skills and problem solving skills .There is a textbook exercise: (ordinary High school curriculum standard experimental textbook people teach A version of mathematics compulsory 2P67 Exercise 1) As shown in Figure 1, in the triangular pyramid V-ABC, VA = VC, AB = BC, verify: VB⊥AC.