IB Math Studies: Arithmetic Sequences Part II

[@rinaboshmaf1473]

i love u so much you literally saved my IB grade

[@xxlachey]

Thank you so much! Got my exams in Nov and your vids are proving to be invaluable for revision!!!!

[@carolineg7097]

thank you so much for doing these videos! :) Thanks to you I finished 4 full questions as opposed to my usual 2.5. My teacher is awful!

[@thomasscanlon7018]

richard, ur the best man!

[@RickParina]

Awesome! Sounds like you did well. I am sure your grade will reflect all the hard work you did!

[@achuguryan]

Hello, these videos are really helpful and understandable. Thank you. But from the 9th minute in the b), shouldn't the regular formula from booklet be used to count the first term. Because formula you used was used for the second term while counting common difference?

[@Gonemobbing]

This helped me out so much my teacher doesn't teach it well she only gives examples and does it once and everybody gets it an I'm one of the only ones that is lost because I need step by step help.

[@RickParina]

When you have an arithmetic sequence like 2, 5 ,8... The common difference can be found by doing 5-2=3 ans 8-5=3. So therefore what I am doing is the same thing with 5k-8-(3k+4)=3k+30-(5k-8). You are using the common difference to find k in this case.

[@jayykhatun6179]

amazing! it 2016 and im using its thankyou

[@lewisarbuckle8718]

Is the answer to question (d) correct? I believed that by following "Un=U1+(n-1)d", you substitue the first term of the sequence which you are using to find the 20th term of. SO "U1" in this case would be '20' since that is the first term of our sequence? I got an answer of 260.

[@saraalaali4528]

Thank you

[@kendoowo3382]

Thank you!

[@Israagroof]

thank youu!

[@RickParina]

Hey thanks for the question... U20 = 20 + (20-1)12 = 248 . I think you might have forgotten to subtract the 1.

[@carolineg7097]

I can't work out how why you've set out the equation the way you have. How come you subtract 2k+4 and then 5k-8 from 3k+20? I messed up the studies paper today and am panicking about tomorrow :/

[@sxuxnxnxy]

Lewis!! Ahahahah!!