Waste less time on Facebook — follow Brilliant.
×

Please help!

\[\int_{0}^{1}\dfrac{x^4+1}{x^6+1}dx=\dfrac{\pi}{3}\].Please prove the above statement.

Note by Adarsh Kumar
1 year, 9 months ago

No vote yet
1 vote

Comments

Sort by:

Top Newest

\[ \int_0^1 \dfrac{x^4+1}{x^6+1} = \int_0^1 \dfrac{x^4+1}{(x^2+1)(x^4 - x^2 + 1)} \]

\[= \int_0^1 \dfrac{x^4-x^2+1}{(x^2+1)(x^4 - x^2 + 1)} + \int_0^1 \dfrac{x^2}{(x^2+1)(x^4 - x^2 + 1)}\]

\[ = \int_0^1 \dfrac{1}{x^2+1} + \int_0^1 \dfrac{x^2}{x^6+1} \]


With \(\displaystyle \int_0^1 \dfrac{x^2}{x^6+1} dx \), substitute \(x^3 = u \Rightarrow \ 3x^2 \ dx = du \) to make it as \(\displaystyle \int_0^1 \dfrac{du}{3(u^2+1)} \).

The rest must be a baby's play for you I guess! Satyajit Mohanty · 1 year, 9 months ago

Log in to reply

@Satyajit Mohanty Nice solution ! Rajdeep Dhingra · 1 year, 9 months ago

Log in to reply

@Satyajit Mohanty Many thanks,bhaiya.I am grateful. Adarsh Kumar · 1 year, 9 months ago

Log in to reply

@Adarsh Kumar Well, while integrating Rational Functions of the form \(\dfrac{P(x)}{Q(x)}\), my first strategy is always to compare the degrees of \(P(x)\) and \(Q(x)\). If \(deg(P(x)) < deg(Q(x))\), I always invoke partial fractions. If \(deg(P(x)) > deg(Q(x) \), turn it into the form \(\dfrac{P(x)}{Q(x)} = R(x) + \dfrac{S(x)}{Q(x)} \) where \(deg(S(x)) < deg(Q(x))\), and then I invoke partial fractions! Satyajit Mohanty · 1 year, 9 months ago

Log in to reply

@Satyajit Mohanty A lot of problems can be cracked by this statergy :) Satyajit Mohanty · 1 year, 9 months ago

Log in to reply

Log in to reply

×

Problem Loading...

Note Loading...

Set Loading...