सिद्ध कीजिए कि `2 cos^(-1).(4)/(5) = cos^(-1).(7)/(25)`

cot[cos^(-1)((7)/(25))]=

सिद्ध कीजिए कि 2tan^(-1)sqrt((b)/(a))=cos^(-1)((a-b)/(a+b))

cos[sin^(-1)(-4//5)-cos^(-1)(4//5)]=

cos(2cos^(-1)(7//25))=

cos^(-1)((3)/(5))+cos^(-1)((4)/(5))=(pi)/(2)

Evaluate cos(sin^(-1)(4/5)+cos^(-1)(2/3))

If |z-25i|le15 , then |maximum arg(z) - minimum arg(z)| equals (A) (pi)/(2)+cos^(-1)((3)/(5)) (B) sin^(-1)((3)/(5))-cos^(-1)((3)/(5)) (C) 2cos^(-1)((4)/(5)) (D) 2cos^(-1)((1)/(5))