How do you evaluate int 1/x^21x2 for [-1, -1/2]?

1 Answer
Oct 23, 2015

We can use the power rule.

int 1/x^2dx = int x^(-2)dx1x2dx=x2dx

int_a^b x^ndx = [(x^(n+1))/(n+1)]|baxndx=[xn+1n+1]""_(a)^(b)ba

= [(b^(n+1))/(n+1)] - [(a^(n+1))/(n+1)]=[bn+1n+1][an+1n+1]

So, let's use this formula to do so.

=> color(blue)(int_(-1)^("-1/2") 1/x^2dx) = int_(-1)^("-1/2") x^(-2)dx-1/211x2dx=-1/21x2dx

= [x^(-1)/(-1)]|_(-1)^"-1/2" = =[x11]-1/21=[-1/x][1x]|_(-1)^"-1/2"-1/21

= [-1/(-"1/2")] - [-1/(-1)]=[11/2][11]

= 2 - 1=21

= color(blue)(1)=1