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Question Number 152201 Answers: 0 Comments: 0

...Integral... I := ∫_0 ^( π) ln (sin(x) ).tan^( −1) (cot(x))dx=^? 0 proof :: .... I := ∫_0 ^( π) ln (sin(x) ). tan^( −1) ( tan((π/2) −x ))dx := ∫_0 ^( π) ((π/2) −x ).ln(sin(x))dx := (π/2) ∫_0 ^( π) ln(sin(x))dx−∫_0 ^( π) xln(sin(x))dx := (π/2) (−π ln (2 )) −J ......( 1 ) J : = ∫_0 ^( π) (π − x) ln (sin(x))dx := π (−π ln(2))−J ∴ J :=((−π^( 2) )/2) ln( 2 ) .......(2) (2) ⇛ (1 ) : I = 0 .........■

$$ \\ $$$$\:\:\:...\mathrm{Integral}... \\ $$$$\:\:\:\:\:\:\:\:\:\:\mathrm{I}\::=\:\int_{\mathrm{0}} ^{\:\pi} {ln}\:\left({sin}\left({x}\right)\:\right).{tan}^{\:−\mathrm{1}} \left({cot}\left({x}\right)\right){dx}\overset{?} {=}\:\mathrm{0} \\ $$$$\:\:\:\:\:{proof}\:::\:.... \\ $$$$\:\:\:\:\:\:\mathrm{I}\::=\:\int_{\mathrm{0}} ^{\:\pi} {ln}\:\left({sin}\left({x}\right)\:\right).\:{tan}^{\:−\mathrm{1}} \left(\:{tan}\left(\frac{\pi}{\mathrm{2}}\:−{x}\:\right)\right){dx} \\ $$$$\:\:\:\:\:\:\::=\:\int_{\mathrm{0}} ^{\:\pi} \left(\frac{\pi}{\mathrm{2}}\:−{x}\:\right).{ln}\left({sin}\left({x}\right)\right){dx} \\ $$$$\:\:\:\:\:\:\:\::=\:\frac{\pi}{\mathrm{2}}\:\int_{\mathrm{0}} ^{\:\pi} {ln}\left({sin}\left({x}\right)\right){dx}−\int_{\mathrm{0}} ^{\:\pi} {xln}\left({sin}\left({x}\right)\right){dx} \\ $$$$\:\:\:\:\:\:\::=\:\frac{\pi}{\mathrm{2}}\:\left(−\pi\:{ln}\:\left(\mathrm{2}\:\right)\right)\:−\mathrm{J}\:\:\:......\left(\:\mathrm{1}\:\right)\:\: \\ $$$$\:\:\:\:\:\:\mathrm{J}\::\:=\:\int_{\mathrm{0}} ^{\:\pi} \left(\pi\:−\:{x}\right)\:{ln}\:\left({sin}\left({x}\right)\right){dx} \\ $$$$\:\:\:\:\:\:\:\:\:\::=\:\pi\:\left(−\pi\:{ln}\left(\mathrm{2}\right)\right)−\mathrm{J} \\ $$$$\:\:\:\:\:\:\:\:\therefore\:\:\:\:\:\mathrm{J}\::=\frac{−\pi^{\:\mathrm{2}} }{\mathrm{2}}\:{ln}\left(\:\mathrm{2}\:\right)\:.......\left(\mathrm{2}\right) \\ $$$$\:\:\:\:\:\:\left(\mathrm{2}\right)\:\Rrightarrow\:\left(\mathrm{1}\:\right)\::\:\:\:\:\:\mathrm{I}\:=\:\mathrm{0}\:.........\blacksquare \\ $$$$ \\ $$

Question Number 152178 Answers: 2 Comments: 1

Solve the system { ((y(√x) + x(√y) = x + y)),(((√x) + (√y) = xy)) :} Find all the real solutions other than x = 0 and y = 0

$$\mathrm{Solve}\:\mathrm{the}\:\mathrm{system} \\ $$$$\begin{cases}{\mathrm{y}\sqrt{\mathrm{x}}\:+\:\mathrm{x}\sqrt{\mathrm{y}}\:=\:\mathrm{x}\:+\:\mathrm{y}}\\{\sqrt{\mathrm{x}}\:+\:\sqrt{\mathrm{y}}\:=\:\mathrm{xy}}\end{cases} \\ $$$$\mathrm{Find}\:\mathrm{all}\:\mathrm{the}\:\mathrm{real}\:\mathrm{solutions}\:\mathrm{other}\:\mathrm{than} \\ $$$$\mathrm{x}\:=\:\mathrm{0}\:\:\mathrm{and}\:\:\mathrm{y}\:=\:\mathrm{0} \\ $$

Question Number 152175 Answers: 1 Comments: 6

what exact value sin 2x if given cos 3x = (2/( (√5)))

$$\mathrm{what}\:\mathrm{exact}\:\mathrm{value}\:\mathrm{sin}\:\mathrm{2x}\:\mathrm{if}\:\mathrm{given} \\ $$$$\:\mathrm{cos}\:\mathrm{3x}\:=\:\frac{\mathrm{2}}{\:\sqrt{\mathrm{5}}} \\ $$

Question Number 152187 Answers: 1 Comments: 1

Please formular for Γ((8/3))

$$\mathrm{Please}\:\mathrm{formular}\:\mathrm{for}\:\:\:\:\:\Gamma\left(\frac{\mathrm{8}}{\mathrm{3}}\right) \\ $$

Question Number 152165 Answers: 2 Comments: 0

∫((sin x)/(sin 3x))dx