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I'm not sure how answers are marked in A level Mathematics exams (if it counts, I'm sitting for the CIE board) but when I am doing practice questions based on a book, sometimes my answer may differ by a few hundredths or tenths (usually the third significant figure). When this happens, I usually assume that my calculation is correct and that the difference simply happens because of a choice I use to use or not use the correct form, not the one rounded off to 3 s.f. Would my marks be affected by these differences in an exam and if they do, when do I know whether I should use the rounded off figure or the exact form?
For instance in the work I've recently done, the question comes in 2 parts, the first is that I need to find the area of the sector and the second is the area of the chord of said sector. What I did was subtract the area of triangle from my previous answer but my answer was off by 2 hundredth. I did the calculation again using the correct form of the sector, not the one rounded to 3 s.f. and got the answer written in the answer booklet.
Would my answer be considered correct?
sin theta = (under root 3 + 1) divided by 2 times under root 2 cos theta = (under root 3 - 1) divided by 2 times under root 2 Find the value of theta. Please look at the shared image.
When we have to measure the argument of a complex number then if we consider theta to be taken clockwise the angle is negative and if we consider taking it anticlockwise the angle is positive. But in case of a complex number the only information I have is which quadrant the number lies in, not it's direction. How can I then measure its argument? I've made many errors because of this confusion, can someone please explain to me in a video lesson?