tan72^(@)

Prove that tan 72^(@)=tan 18^(@)+2 tan 54^(@)

The numerical value of cot 18^(@) (cot 72^(@) cos^(2) 22^(@) + (1)/(tan 72^(@) sec^(2) 68^(@))) is

Without using trigonometric tables, evaluate. "sin"^(2)34^(@)+"sin"^(2)56^(@)+2" tan"18^(@)"tan"72^(@)-"cot"^(2)30^(@)

Prove that: (i) cos55^(@)sin 35^(@)+sin 55^(@)cos 35^(@)=1 (ii) (tan 72^(@))/(cot 18^(@))-(cot 72^(@))/(tan18^(@))=0 (iii) sec70^(@)sin 20^(@)+cosec 70^(@)cos 20^(@)=2

What is the value of (tan 9^(@) tan 23^(@) tan 60^(@) tan67^(@) tan 81^(@))/("cosec"^(2)72^(@)+cos^(2)15^(@)-tan^(2)18^(@)+cos^(2)75^(@))? (a) (1)/(2 sqrt(3)) (b) (sqrt(3))/(2) (c) (1)/(sqrt(3)) (d) 2 sqrt(3)

Evaluate : (i) (sin18^@)/(cos72^@) (ii) (tan26^@)/(cot64^@) (iii) cos48^@-sin42^@ (iv) c o s e c 31^@sec59^@

Find the value of (sec(15)^(@))/(cos ec(75)^(@))+(sin(72)^(@))/(cos(18)^(@))-(tan(30)^(@))/(cot(57)^(@))

Evaluate the following : (sin72^(@)+cos18^(@))(sin72^(@)-cos18^(@))