A-LevelMathematicsDifferentiation9709/32 · Oct/Nov 2019 · Q25 Marks
The curve with equation y = e⁻²ˣ / (1-x²) has a stationary point in the interval −1 < x < 1. Find dy/dx and hence find the x-coordinate of this stationary point, giving the answer correct to 3 decimal places.
- (a)The curve with equation y = e⁻²ˣ / (1-x²) has a stationary point in the interval −1 < x < 1. Find dy/dx and hence find the x-coordinate of this stationary point, giving the answer correct to 3 decimal places.[5]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2019). The mark or mark type is shown in brackets.
- [M1] Use correct quotient rule or correct product rule
- [A1] Obtain correct derivative in any form
- [M1] Equate derivative to zero and obtain a 3 term quadratic in x
- [A1] Obtain a correct 3-term equation e.g. 2x²+2x-2=0 or x² +x=1
- [A1] Solve and obtain x = 0.618 only
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