Is `costheta = x+1/x` possible for x in R?

Is costheta=(x+y)/(x-y) possible if x > y > 0?

Prove that x+1/x=sintheta is not possible for all x in R

Is costheta=(x^2-y^2)/(x^2+y^2) possible if x, y in R and 0 < theta < 90^@ ?

Find the values of cos theta which satisfy the equation 2costheta=x+1/x if x in R

Show that sec^2theta=(4xy)/(x+y)^2 is possible only if x = y

If sintheta - costheta = 1 , then prove that sintheta + costheta =+-1

Eliminate theta and phi x costheta+y sintheta=a , y costheta-x sintheta=b

Let |(3,y),(x,1)|=|(3,2),(4,1)| , find the possible values of x,y,epsilonN .

A function f : R rarr R is defined as f(x)=10x+7 for all x in R . Find the function g : R rarr R such that gof=fog=I_R .