Menu Close

prove-that-0-2020-x-x-x-x-dx-808-




Question Number 88177 by M±th+et£s last updated on 08/Apr/20
prove that    ∫_0 ^(2020) (x−[x])(√(x−[x])) dx=808
$${prove}\:{that} \\ $$$$ \\ $$$$\int_{\mathrm{0}} ^{\mathrm{2020}} \left({x}−\left[{x}\right]\right)\sqrt{{x}−\left[{x}\right]}\:{dx}=\mathrm{808} \\ $$
Answered by TANMAY PANACEA. last updated on 08/Apr/20
∫_0 ^1 (x−0)(√(x−0)) dx+∫_1 ^2 (x−1)((√(x−1)) dx+..+∫_(2019) ^(2020) (x−2019)(√(x−2019)) dx  =∣(x^(5/2) /(5/2))∣_0 ^1 +∣(((x−1)^(5/2) )/(5/2))∣_1 ^2 +..+∣(((x−2019)^(5/2) )/(5/2))∣_(2019) ^(2020)   ((5I)/2)=(1^(5/2) −0^(5/2) )+(1^(5/2) −0^(5/2) )+..+(1^(5/2) −0^(5/2) )  =2020  I=2×404=808
$$\int_{\mathrm{0}} ^{\mathrm{1}} \left({x}−\mathrm{0}\right)\sqrt{{x}−\mathrm{0}}\:{dx}+\int_{\mathrm{1}} ^{\mathrm{2}} \left({x}−\mathrm{1}\right)\left(\sqrt{{x}−\mathrm{1}}\:{dx}+..+\int_{\mathrm{2019}} ^{\mathrm{2020}} \left({x}−\mathrm{2019}\right)\sqrt{{x}−\mathrm{2019}}\:{dx}\right. \\ $$$$=\mid\frac{{x}^{\frac{\mathrm{5}}{\mathrm{2}}} }{\frac{\mathrm{5}}{\mathrm{2}}}\mid_{\mathrm{0}} ^{\mathrm{1}} +\mid\frac{\left({x}−\mathrm{1}\right)^{\frac{\mathrm{5}}{\mathrm{2}}} }{\frac{\mathrm{5}}{\mathrm{2}}}\mid_{\mathrm{1}} ^{\mathrm{2}} +..+\mid\frac{\left({x}−\mathrm{2019}\right)^{\frac{\mathrm{5}}{\mathrm{2}}} }{\frac{\mathrm{5}}{\mathrm{2}}}\mid_{\mathrm{2019}} ^{\mathrm{2020}} \\ $$$$\frac{\mathrm{5}{I}}{\mathrm{2}}=\left(\mathrm{1}^{\frac{\mathrm{5}}{\mathrm{2}}} −\mathrm{0}^{\frac{\mathrm{5}}{\mathrm{2}}} \right)+\left(\mathrm{1}^{\frac{\mathrm{5}}{\mathrm{2}}} −\mathrm{0}^{\frac{\mathrm{5}}{\mathrm{2}}} \right)+..+\left(\mathrm{1}^{\frac{\mathrm{5}}{\mathrm{2}}} −\mathrm{0}^{\frac{\mathrm{5}}{\mathrm{2}}} \right) \\ $$$$=\mathrm{2020} \\ $$$${I}=\mathrm{2}×\mathrm{404}=\mathrm{808} \\ $$
Commented by M±th+et£s last updated on 08/Apr/20
god bless you sir
$${god}\:{bless}\:{you}\:{sir} \\ $$
Commented by TANMAY PANACEA. last updated on 08/Apr/20
most welcome sir...
$${most}\:{welcome}\:{sir}… \\ $$

Leave a Reply

Your email address will not be published. Required fields are marked *