Answering Questions without Calculators

[bescherelle]

[size=4][b]This thread is dedicated to IB students like me who love to use calculators. [/size]

I came across this question without using a calculator and got stuck. btw im in pre-ib maths.

13.
(a) Consider the equation 2 3sin x−11sinx+6 = 0.

(i) Find the two values of sin x which satisfy this equation.

(ii) Solve the equation, for 0 ≤x≤180 .
[/b]
So basically I did it up to.... sin x= 2/3 or sin x= 3 which answers part i.

then i did part ii. and i know that immediately sin x=3 is invalid/error.

so im left with sin x= 2/3

either im missing something or havent been taught it but its impossible to do that even with knowing the special angles. After I used the calculator the answers were 41.8 degrees and 138 degrees.

Feel free to ask any questions that you are unable to solve without a calculator and we all can learn a few tricks here and there.

edit- this question was from november 2003 paper 1[b][/b]

Edited May 27, 2008 by bescherelle

[__inthemaking]

Um, I don't think this question will be asked of you because it's from 2003, which is the OLD syllabus.

In the old syllabus, we were allowed to use calculators. It's only the new syllabus (2008 and onwards) that you can't use calculators for paper 1, so the questions are considerably easier, and you will not be asked to complete hard questions like this without the use of your calculator.

Edited May 27, 2008 by __inthemaking