" 19."quad (i)sin^(2)67^(@)+sin^(2)23^(@)=cos^(2)89^(@)+cos^(2)1^(@)=1

The value of the determinant Delta=|{:(sin^(2)23^(@)" "sin^(2)67^(@)" "cos180^(@)),(-sin^(2)67^(@)" "-sin^(2)23^(@)" "-cos180^(@)),(cos180^(@)" "sin^(2)23^(@)" "sin^(2)67^(@)):}| is

If (cos^(4)A)/(cos^(2)B)+(sin^(4)A)/(sin^(2)B)=1 then prove that (i)sin^(2)A+sin^(2)B=2sin^(2)A sin^(2)B(ii)(cos^(4)B)/(cos^(2)A)+(sin^(4)B)/(sin^(2)A)=1

sin 67(1)/(2)^(@)+cos67(1)/(2)^(@) is equal to

sin (67(1)/2)^(@)+cos(67(1)/2)^(@) is equal to

sin 67(1)/(2)^(@)+cos67(1)/(2)^(@) is equal to

Show that (i) sin^(8)A-cos^(8)A=(sin^(2)A-cos^(2)A)(1-2sin^(2)A.cos^(2)A) (ii) (1)/(sec A-tan A)-(1)/(cos A)=(1)/(cos A)-(1)/(sec A + tan A)

Show that (i) sin^(8)A-cos^(8)A=(sin^(2)A-cos^(2)A)(1-2sin^(2)A.cos^(2)A) (ii) (1)/(sec A-tan A)-(1)/(cos A)=(1)/(cos A)-(1)/(sec A + tan A)

Show that (i) sin^(8)A-cos^(8)A=(sin^(2)A-cos^(2)A)(1-2sin^(2)A.cos^(2)A)

If sin^(-1)x = theta + beta and sin^(-1)y = theta - beta , then 1+xy= (i) sin^(2) θ+sin^(2) β (ii) sin^(2) θ+cos^(2) β (iii) cos^(2) θ+cos^(2) β (iv) cos^(2) θ+sin^(2) β