" Q.8If "pi<=x<=2 pi," then "cos^(-1)(cos x)" is equal to "

Using the concept of energy density , show that the total energy stored by a shell of radius R and charge Q is (Q^(2))/( 8 pi epsilon_(0)R)

Using the concept of energy density , show that the total energy stored by a shell of radius R and charge Q is (Q^(2))/( 8 pi epsilon_(0)R)

Find the Values of sin (pi/8) ,cos (pi/ 8) ,sec (pi/8) ,cosec (pi/8) ,tan (pi/8) and Cot (pi/8)

((1+cos. pi/8+isin. pi/8)/(1+cos. pi/8- isin. pi/8))^(8)=

Prove that "cos"^(8) (pi)/(8)+ "cos"^8 (3pi)/(8)+"cos"^(8) (5pi)/(8)+"cos"^(8)(7pi)/(8)=(17)/(16) ,

Evaluate : cos ""(pi)/(8) sin ""(pi)/(8)

cos^2 ""(pi)/(8) + cos ^2 ""(3 pi)/(8) + cos ^2 ""(5 pi)/(8) + cos ^2 ""(7 pi)/(8) is

((1 + "cos"(pi)/(8) -i "sin"(pi)/(8))/(1 + "cos"(pi)/(8) + i "sin" (pi)/(8)))^(12)=

The value of cos(pi)/(8)cos(3 pi)/(8)cos(5 pi)/(8)cos(7 pi)/(8) is equal to