Help Solving Integral Limit: x to 1

[erogol]

lim x \int cost / t^2 (integral x to 1) x goes infitine

 

[CompuChip]

Did you mean:
\lim_{x \to \infty} \int_x^1 \frac{\cos t}{t^2} \, dt
?

 

[erogol]

yes:) but there is a x before the integral

 

[MathematicalPhysicist]

Hint: t is in [x,1] i.e 1/t^2 is in [1,1/x^2].

 

[intrepid_nerd]

integrate via parts and keep track of your signs