Which of the following is not always true? `|a+b|^2=|a|^2+|b|^2`,if a and b are perpendicular to each other

if the tangents on the ellipse 4x^(2)+y^(2)=8 at the points (1,2) and (a,b) are perpendicular to each other then a^(2) is equal to

if the tangents on the ellipse 4x^(2)+y^(2)=8 at the points (1,2) and (a,b) are perpendicular to each other then a^(2) is equal to

if the tangents on the ellipse 4x^(2)+y^(2)=8 at the points (1,2) and (a,b) are perpendicular to each other then a^(2) is equal to

Which is the following is always true ? (a) If a lt b, " then " a^2 lt b^2 (b ) If a lt b "then " 1/a gt 1/b ( c) If a lt b , " then " |a| lt |b|

Which is the following is always true ? (a) If a lt b, " then " a^2 lt b^2 (b ) If a lt b "then " 1/a gt 1/b ( c) If a lt b , " then " |a| lt |b|

Which is the following is always true ? (a) If a lt b, " then " a^2 lt b^2 (b ) If a lt b "then " 1/a gt 1/b ( c) If a lt b , " then " |a| lt |b|

Which is the following is always true ? (a) If a lt b, " then " a^2 lt b^2 (b ) If a lt b "then " 1/a gt 1/b ( c) If a lt b , " then " |a| lt |b|

Factorize each of the following expressions : 1-2a b-(a^2+b^2)

Which of the following statements are true and which are false? (a) The diagonals of a parallelogram are equal. (b) The diagonals of a rectangle are perpendicular to each other. ( c) The diagonals of a rhombus are equal.