Jump to content

Points or no points

Recommended Posts

What up guys.

Just got a question regarding the marking system for externals.

Simply, I have answered a trigo question in paper 1 that was asking for me to find "tan (2x)" with "cos (x)" given in fraction form.

Well..I used the tan (2x) formula to solve as shown here (the 3rd one) ->Image result for tan 2x formula

After answering the paper, I was checking my answers. Then I suddenly recalled "tan (2x)" formula isn't included in the SL syllabus.

The markscheme only showed using " [sin (2x)] / [cos (2x)]" to solve the question, nothing related to the 3rd formula in the shown above. In fact, it was worth 6 points if I'm not mistaken.

If ever I use the tan (2x) formula above, will I be able to receive full marks? I have already inquired this to my math teacher, he however doubt to answer as he wasn't sure.


Would really appreciate your help. Thanks in advance!

Edited by mrunknown

Share this post

Link to post
Share on other sites

An examiner should give you the points assuming you used the first two formulas and worked out the answer from there, regardless of whether it was in the syllabus or a simpler way was available. If IB didn't intend that, they'd outsource the work to factory workers rather than math teachers who would be able to recognize some basic trig. formulas.

  • Like 1

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.