" 28."cos((x)/(1+sqrt(x)))

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

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

Lt_(x to-1) ((sqrt(pi))-sqrt(cos^(-1)x))/(sqrt(x+1))=

lim_(x rarr(-1)^(+))(sqrt(pi)-sqrt(cos^(-1)x))/(sqrt(x+1)) is equal to

If x in (pi, 2pi) , prove that ((sqrt(1+cosx))+(sqrt(1-cos x)))/((sqrt(1+cos x)) -sqrt(1-cos x)) = cot(pi/4 +x/2)

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