Question

Say True or False
The value of the expression $({\cos }^2{23}^{\circ }-{\sin }^2{67}^{\circ })$ is positive.

• A. True
• B. False
• C. Ambiguous
• D. Data insufficient
  

Answer 1

The correct option is B False

$=co{s}^2{23}^0-si{n}^2{67}^0$
$=co{s}^2{23}^0-si{n}^2({90}^0-{23}^0)$
$=co{s}^2{23}^0-co{s}^2{23}^0$
$=0$