" 13."sqrt(x+4)+(sin36^(@)+cos36^(@))/(cos54''+sin54^(@))

Prove that (sin36^(@)+cos36^(@))/(cos54^(@)+sin54^(@))=1

sin36^(@)+cos36^(@)=sqrt(2)cos9^(@)

cos54^(@)cos36^(@)-sin54^(@)sin36^(@)=0

sin9^(@)+cos9^(@)=sqrt(2)sin54^(@)

Prove that (sin36^(@))/(cos54^(@))+(cos36^(@))/(sin54^(@))=2

cos(36^(@)-A)cos(36^(@)+A)+cos(54^(@)+A)cos(54^(@)-A)=

cos ^ (2) (26 ^ (@)) + cos64 ^ (@) sin26 ^ (@) + (tan36 ^ (@)) / (cot54 ^ (@))

Evaluate without using trigonometric tables : "cos"^(2) 26^(@)+"cos" 64^(@)"sin" 26^(@)+("tan" 36^(@))/("cot" 54^(@))

Prove that sin 36^(@) + cos 36^(@) = sqrt(2) cos 9^(@)

Evalute (f) (sin36^(@))/(cos54^(@))-(sin54^(@))/(cos36^(@))