 Hello and welcome to the session. In this session we discussed the following question which says, simplify the expression cot inverse of 1 upon square root of x square minus 1. Let's proceed with the solution now. We need to simplify the expression cot inverse of 1 upon square root of x square minus 1. So here first of all we take left x v equal to sec theta. Therefore the given expression that is cot inverse of 1 upon square root of x square minus 1 is equal to cot inverse 1 upon square root of, in place of x we put sec theta. So this would be square root of sec square theta minus 1. Now since we know that sec square theta is equal to 1 plus tan square theta. So this means that sec square theta minus 1 is equal to tan square theta. So this expression would be equal to cot inverse of 1 upon square root of tan square theta. That is in place of sec square theta minus 1 we put tan square theta. And so this is equal to cot inverse of 1 upon tan theta. Or this is equal to cot inverse of cot theta as we know that cot theta is equal to 1 upon tan theta. And so this is equal to theta. Since we have taken x to be equal to sec theta. So this implies that theta is equal to sec inverse x. And so this is equal to sec inverse x. So I am simplifying the expression cot inverse of 1 upon square root of x square minus 1 we get sec inverse x. So this is our final answer. This completes the session. Hope you have understood the solution of this question.