`cos25^(0)cos35^(0)-sin10^(0)sin20^(0)`,

The smallest positive value of x (in degrees) for whichcos tan x=(cos5^(@)cos20^(@)+cos35^(@)cos50^(@)-sin50^(@)sin20^(@)-sin35^(@)sin50^(@))/(sin5^(@)cos20^(@)-sin35^(@)cos50^(@)+cos5^(@)sin20^(@)-cos35^(@)sin50^(@))

Evaluate the following: cos47^(0)cos13^(0)-sin47^(0)sin13^(@)

Find the least positive x in degree for which tan x= (cos5^(@)cos20^(@)+cos35^(@)cos50^(@)-sin5^(@)sin20^(@)-sin35^(@)sin50^(@))/(sin5^(@)cos20^(@)-sin35^(@)cos50^(@)+cos5^(@)sin20^(@)-cos35^(@)sin50^(@))

Prove that : (i) sin42^(@)cos48^(@)+sin48^(@)cos42^(@)=1 (ii) cos70^(@)cos20^(@)-sin70^(@)sin20^(@)=0

(cos20^(0)+8sin70^(0)sin50^(@)sin10^(0))/(sin^(2)80^(@)) is equal to

Which of the following number(s) is/are rational? (a)sin 15^(0)(b)cos15^(0)(c)sin15^(0)cos15^(0)(d)sin15^(0)cos75^(0)

If cos56^(0)+cos58^(0)-cos66^(0)-4cos28^(0)-cos29^(@)sin33^(@)=lambda then |2 lambda|=

If 1+cos56^(0)+cos58^(0)-cos66^(0)=k cos28^(0)cos29^(@)sin33^(@) then the value of k is

Show that sin70^(0)cos10^(0)-cos70^(0)sin10^(0)=(sqrt(3))/(2)

Show that: cos70^(@)*cos10^(0)+sin70^(@)*sin10^(@)=(1)/(2)