Solve `cos((sqrt(2)+1)/2) x .cos((sqrt(2)-1)/2)x=1`

cos^(-1)x = tan^(-1)x , then: a. x^2=((sqrt(5)-1)/2) b. x^2=((sqrt(5)+1)/2) c. sin(cos^(-1)x)=((sqrt(5)-1)/2) d. tan(cos^(-1)x)=((sqrt(5)-1)/2)

Solve (sqrt(3)-1)cos x+(sqrt(3)+1)sin x=2

cos^(-1)(sqrt(1+cos x)/2)

If x takes negative permissible values , then sin^(-1) x= a) cos^(-1)sqrt(1-x^2) b) -cos^(-1)sqrt(1-x^2) c) cos^(-1)sqrt(x^2-1) d) pi-cos^(-1)sqrt(1-x^2)

cos^-1((x)/sqrt(1+x^2))

Solve : cos^(-1)(1/2x^2+sqrt(1-x^2).sqrt(1-(x^2)/4))=cos^(-1)x/2-cos^(-1)xdot

cos 2x=(sqrt(2)+1)(cos x - (1)/(sqrt(2))), cos x ne (1)/(2) rArr x in

"cos" 2x =(sqrt(2) + 1) ("cos"x- (1)/(sqrt(2))),"cos" x ne (1)/(2) rArr x in

"cos" 2x =(sqrt(2) + 1) ("cos"x- (1)/(sqrt(2))),"cos" x ne (1)/(2) rArr x in