Current location - Training Enrollment Network - Mathematics courses - Who can help me solve a math problem of the sprint paper in Qujing No.1 Middle School in 2009?
Who can help me solve a math problem of the sprint paper in Qujing No.1 Middle School in 2009?
Translation AD intersects with E, and CD intersects with F, then EF is the center line of triangle ACD.

Let the side length of a regular tetrahedron be a.

Then EF= 1/2a BE=√3/2a BF=√3/2a.

From cosine theorem, angle BEF=? The answer should be D.

Related articles
  • Not math.
  • Is there a math class in the university?
  • Differences between authorizations 304 and 404
  • Senior high school mathematics compulsory course
  • Hongletong mathematics
  • What should be compared between math reading and writing in the next volume of senior one?
  • Reflections on the teaching of fractional division under the new curriculum standard
  • Graduate admission scores of Shenzhen University in 2023
  • Contents of compulsory mathematics 2 and 3 in senior high school
  • How to educate people in primary school mathematics classroom

    • copyright 2024 Training Enrollment Network All rights reserved