Cot2θ+tanθ = ? Write Answer With Explanation...

2 Answers
May 2, 2018

=csc2theta

Explanation:

We know that,

(1)tan2x=(2tanx)/(1-tan^2x)

(2)sin2x=(2tanx)/(1+tan^2x)

Using (1)and(2)

cot2theta+tantheta=1/tan(2theta)+tantheta

=1/((2tantheta)/(1-tan^2theta))+tantheta

=(1-tan^2theta)/(2tantheta)+tantheta

=(1-tan^2theta+2tan^2theta)/(2tantheta)

=(1+tan^2theta)/(2tantheta)

=1/((2tantheta)/(1+tan^2theta))

=1/(sin2theta)

=csc2theta

May 2, 2018

=csc2theta

Explanation:

We know that,

color(red)((1)cosAcosB+sinAsinB=cos(A-B)

color(blue)((2)cscA=1/sinA

Now,

cot2theta+tantheta=(cos2theta)/(sin2theta)+sintheta/costheta

=color(red)((cos2thetacostheta+sin2thetasintheta))/(sin2thetacostheta)..tocolor(red)(Apply(1)

=color(red)((cos(2theta-theta)))/(sin2thetacostheta)

=costheta/(sin2thetacostheta)

=color(blue)(1/(sin2theta)...toApply(2)

=color(blue)(csc2theta