MathematicsMedium210×since 2002Q3396If In=∫π4π2cotnx dx{I_n} = \int\limits_{{\pi \over 4}}^{{\pi \over 2}} {{{\cot }^n}x\,dx}In=4π∫2πcotnxdx, then :A1I2+I4,1I3+I5,1I4+I6{1 \over {{I_2} + {I_4}}},{1 \over {{I_3} + {I_5}}},{1 \over {{I_4} + {I_6}}}I2+I41,I3+I51,I4+I61 are in A.P.BI₂ + I₄, I₃ + I₅, I₄ + I₆ are in A.P.C1I2+I4,1I3+I5,1I4+I6{1 \over {{I_2} + {I_4}}},{1 \over {{I_3} + {I_5}}},{1 \over {{I_4} + {I_6}}}I2+I41,I3+I51,I4+I61 are in G.P.DI₂ + I₄, (I₃ + I₅)², I₄ + I₆ are in G.P.Check answerSkip