I came across a Maths SL question today. Wasn't sure if this answer was correct from this certain Maths SL textbook.
I always thought that dominate powers held true. The back of the back has the answer as "D.N.E (increases without bound)"
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My answer would have been
| B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor
| B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor
Yes, you can use (a, b). You can read about the two notations here: https://en.wikipedia.org/wiki/Interv...ding_endpoints .
| B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor
By the way this is a question from Newington, seems like the staff don't know how to teach the subject properly there.
By setting the discriminant to less than equal to zero, we are trying to prove that there are no solutions for the real values of x, using the quadratics roots formula. Right?
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Why do you think they don't know how to teach the subject properly there? Is it something their worked answers said?
The reason we can set the discriminant to be less than or equal to 0 is that we are told the quadratic is non-negative for all real x ("non-negative definite"). This implies (since it's a quadratic with real coefficients) that its discriminant is non-positive.
Last edited by InteGrand; 9 Apr 2017 at 11:28 PM.
I'll take your word for it Integrand, I am still confused as to what non-negative means in this case.
I thought the discriminant for sure was reading the question first up.
| B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor
Take back my comment about the school. Don't know much about the school personally except I have bumped across a couple of students from here. I hear a lot of complaints about students about how well a teacher can teach or can't teach a particular subject. (from all schools and universities). I say to any student or parent, never put the blame on the school/teachers or tutors. They only play about 1/5th of the role in the outcome of a grade.
I think from memory one of the authors from the Cambridge maths textbook for HSC came from there. Julie something.......
Also I have driven past Stanmore and that school fairly often.
| B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor
| B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor
You are correct. Easy verification by substitution then expansion and grouping of reals and imaginary components which I know you know, so why did you have doubts?
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