Question and Answers Forum

All Questions      Topic List

Algebra Questions

Previous in All Question      Next in All Question      

Previous in Algebra      Next in Algebra      

Question Number 200035 by ajfour last updated on 12/Nov/23

Commented by ajfour last updated on 12/Nov/23

Find equation of parabola having             same curvature as sin x,                      at shown point

$${Find}\:{equation}\:{of}\:{parabola}\:{having}\: \\ $$$$\:\:\:\:\:\:\:\:\:\:{same}\:{curvature}\:{as}\:\mathrm{sin}\:{x}, \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:{at}\:{shown}\:{point} \\ $$

Commented by Matica last updated on 13/Nov/23

Use approxitation methods:  −Maclurine serie  −Pade approximation

$${Use}\:{approxitation}\:{methods}: \\ $$$$−{Maclurine}\:{serie} \\ $$$$−{Pade}\:{approximation} \\ $$

Answered by mr W last updated on 12/Nov/23

y=sin x at x=(π/2):  y′=cos x∣_(x=(π/2)) =0  y′′=−sin x∣_(x=(π/2)) =−1  R=∣(((1+0)^(3/2) )/(−1))∣=1  y=−a(x−(π/2))^2 +1 at x=(π/2):  y′=−2a(x−(π/2))∣_(x=(π/2)) =0  y′′=−2a  R=∣(((1+0)^(3/2) )/(−2a))∣=(1/(2a))=1 ⇒a=(1/2)    ⇒the parabola is y=−(1/2)(x−(π/2))^2 +1

$${y}=\mathrm{sin}\:{x}\:{at}\:{x}=\frac{\pi}{\mathrm{2}}: \\ $$$${y}'=\mathrm{cos}\:{x}\mid_{{x}=\frac{\pi}{\mathrm{2}}} =\mathrm{0} \\ $$$${y}''=−\mathrm{sin}\:{x}\mid_{{x}=\frac{\pi}{\mathrm{2}}} =−\mathrm{1} \\ $$$${R}=\mid\frac{\left(\mathrm{1}+\mathrm{0}\right)^{\frac{\mathrm{3}}{\mathrm{2}}} }{−\mathrm{1}}\mid=\mathrm{1} \\ $$$${y}=−{a}\left({x}−\frac{\pi}{\mathrm{2}}\right)^{\mathrm{2}} +\mathrm{1}\:{at}\:{x}=\frac{\pi}{\mathrm{2}}: \\ $$$${y}'=−\mathrm{2}{a}\left({x}−\frac{\pi}{\mathrm{2}}\right)\mid_{{x}=\frac{\pi}{\mathrm{2}}} =\mathrm{0} \\ $$$${y}''=−\mathrm{2}{a} \\ $$$${R}=\mid\frac{\left(\mathrm{1}+\mathrm{0}\right)^{\frac{\mathrm{3}}{\mathrm{2}}} }{−\mathrm{2}{a}}\mid=\frac{\mathrm{1}}{\mathrm{2}{a}}=\mathrm{1}\:\Rightarrow{a}=\frac{\mathrm{1}}{\mathrm{2}} \\ $$$$ \\ $$$$\Rightarrow{the}\:{parabola}\:{is}\:{y}=−\frac{\mathrm{1}}{\mathrm{2}}\left({x}−\frac{\pi}{\mathrm{2}}\right)^{\mathrm{2}} +\mathrm{1} \\ $$

Commented by ajfour last updated on 13/Nov/23

yes sir, this is perfectly correct.  Thanks.

$${yes}\:{sir},\:{this}\:{is}\:{perfectly}\:{correct}. \\ $$$${Thanks}. \\ $$

Commented by mr W last updated on 12/Nov/23

Terms of Service

Privacy Policy

Contact: info@tinkutara.com