" If "sec(x+alpha)+sec(x-alpha)=2sec x," prove that "cos x=+-sqrt(2)cos(alpha)/(2)

If sec(phi+alpha)+sec(phi-alpha)=2sec phi, prove that cos phi=+-sqrt(2)(cos alpha)/(2)

If sec(theta+alpha)+sec(theta-alpha)=2sec theta, prove that cos theta=+-sqrt(2)(cos alpha)/(2)

If sec(phi+alpha) + sec (phi-alpha) = 2 sec phi , prove that cos phi = pm sqrt(2) "cos"(alpha)/(2) , ( phi ne (pi)/(2)) .

If sec(phi+alpha)+sec(phi-alpha)=2secphi show that cosphi=+-sqrt2cosfrac{alpha}{2}

If sec(theta+alpha)+sec(theta-alpha)=2sec theta and cos alpha!=1 , prove that cos theta=+-sqrt"cos"(alpha)/2

If sec(theta+alpha)+sec(theta-alpha)=2sec theta then show that cos^(2)theta=1+cos alpha

If sec(theta+alpha)+sec(theta-alpha)=2sec theta then show that cos^(2)theta=1+cos alpha

If x sin alpha = y cos alpha, prove that : x/(sec 2alpha) + y/(cosec 2 alpha) = x

If x sin alpha=y cos alpha, prove that :(x)/(sec2 alpha)+(y)/(cos ec2 alpha)=x

If sec^(2)alpha+cos^(2)alpha=2 , then find the value of sec alpha+ cos alpha .