[" 7."[(cos^(4)A-sin^(4)A)" is equal to "],[[" (a) "1-2cos^(2)A," (b) "2sin^(2)A-1],[" (c) "sin^(2)A-cos^(2)A," (d) "2cos^(2)A-1],[" Ans : (d) "2cos^(2)A-1]]]

cos^(4)A-sin^(4)A is equal to 2cos^(2)A+1(b)2cos^(2)A-1(c)2sin^(2)A-1( d) 2sin^(2)A+1

cos^4A-sin^4A is equal to (a) 2cos^2A+1 (b) 2cos^2A-1 (c) 2sin^2A-1 (d) 2sin^2A+1

17*cos^(4)theta-sin^(4)theta is equal to (a)1-2sin^(2)((theta)/(2))(b)2cos^(2)theta-1(c)1+2sin^(2)((theta)/(2))(d)1+2cos^(2)theta

cos^4theta- sin^4theta is equal to.............. (a) 1 -2 sin^2(theta/2) (b) 2cos^2theta-1 (c) 1+2sin^2(theta/2) (d) 1+2cos^2theta

sin^(6)A+cos^(6)A+3sin^(2)A cos^(2)A=0 b.1c2d.3

cos(A+B)*cos(A-B)= (a) sin^2A-cos^2B (b) cos^2A-sin^2B (c) sin^2A-sin^2B (d) cos^2A-cos^2B

if cos A+cos^(2)A=1 , then sin^(2)A+sin^(4)A=1

Prove the following identities: sin^(4)A-cos^(4)A=sin^(2)A-cos^(2)A=2sin^(2)A-1=1-2cos^(2)A

Prove that: ((1) / (sec ^ (2) A-cos ^ (2) A) + (1) / (cos ec ^ (2) A-sin ^ (2) A)) sin ^ (2) A cos ^ (2) A = (1-sin ^ (2) A cos ^ (2) A) / (2 + sin ^ (2) A cos ^ (2) A)

((1) / (sec ^ (2) A-cos ^ (2) A) + (1) / (cos ec ^ (2) A-sin ^ (2) A)) sin ^ (2) A cos ^ (2) A = (1-sin ^ (2) A cos ^ (2) A) / (2 + sin ^ (2) A cos ^ (2) A)