How do you find the value of sec [Cot^-1 (-6)]sec[cot1(6)]?

1 Answer
Mar 26, 2018

-sqrt(37)/6376

Explanation:

We know that,
color(red)((1)cot^-1(-x)=pi-cot^-1x(1)cot1(x)=πcot1x
color(red)((2)sec(pi-theta)=-sectheta(2)sec(πθ)=secθ
color(red)((3)cot^-1x=tan^-1(1/x), x > 0(3)cot1x=tan1(1x),x>0
color(red)((4)tan^-1x=cos^-1(1/(sqrt(1+x^2)))(4)tan1x=cos1(11+x2)
color(red)((5)cos^-1x=sec^-1(1/x)(5)cos1x=sec1(1x)
color(red)((6)sec(sec^-1x)=x(6)sec(sec1x)=x
Here,

sec(cot^-1(-6))=sec(pi-cot^-1(6))...toApply color(red)((1)

=-sec(cot^-1(6)).......toApply color(red)((2)

=-sec(tan^-1(1/6)).........toApply color(red)((3)

=-sec(cos^-1(1/(sqrt(1+(1/6)^2))))......toApply color(red)((4)

=-sec(cos^-1(1/(sqrt(1+1/36))))

=-sec(cos^-1(6/(sqrt(37))))

=-sec(sec^-1(sqrt(37)/6)).......to Apply color(red)((5)

=-sqrt(37)/6...........toApply color(red)((6)