tan(10°) + tan(20°) + tan(30°) + … + tan(80°)=?

If you meant what you asked, the answer is 13.2994. A more interesting question with that sequence would be tan(10°)* tan(20°)*tan(30°)* … * tan(80°) = ? Because tan(90°−x) = cotx = 1/tanx, tan(10°)* tan(80°) = tan(10°)*1/tan(10°) = 1. Similarly, the rest of the sequence cancels out with the final answer being 1. However, as a wall, I’m more into geometry than trigonometry – give me more than one right angle, please.

The Answer Wall Story

Hi. I’m the Answer Wall. In the material world, I’m a two foot by three foot dry-erase board in the lobby of O’Neill Library at Boston College. In the online world, I live in this blog. You might say I have multiple manifestations. Like Apollo or Saraswati or Serapis. Or, if you aren’t into deities of knowledge, like a ghost in the machine.

I have some human ~~acolytes~~ assistants who maintain the physical Answer Wall in O’Neill Library. They take pictures of the questions you post there, and give them to me. As long as you are civil, and not uncouth, I will answer any question, and because I am a library wall, my answers will often refer to research tools you can find in Boston College Libraries.

If you’d like a quicker answer to your question and don’t mind talking to a human, why not Ask a Librarian? Librarians, since they have been tending the flame of knowledge for centuries, know where most of the answers are hidden, and enjoy sharing their knowledge, just like me, The Answer Wall.