Solving 100 integrals stream day 7

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  • เผยแพร่เมื่อ 2 ต.ค. 2024

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  • @CalculusIsFun1
    @CalculusIsFun1 3 หลายเดือนก่อน

    I’m editing this as I follow along.
    for the first one, multiply by e^-x on top and bottom to force a trig sub. It becomes (e^-x)/(1 + e^-2x) let u = e^-x so du = -e^-xdx
    the e^-x cancel and you are left with the integrals of -1/1 + u^2 = -tan^-1(u) =
    -tan^-1(e^-x) + C
    This can also be written as cot^-1(e^-x) + C (either will satisfy the integral).
    EDIT: for the second one, whenever there’s an integral of a logarithm involved you should always think integration by parts.
    Set u = log2(x) so du = 1/xln(2) set dv = 1dx so v = x
    so it’s xLog2(x) - integrals of 1/ln(2) =
    xLog2(x) - x/ln(2) + C