Answer:
cos45° = [tex]\frac{1}{\sqrt{2} }[/tex] = [tex]\frac{\sqrt{2} }{2}[/tex]
Step-by-step explanation:
Using the 45- 45- 90 triangle with legs 1, 1 and hypotenuse [tex]\sqrt{2}[/tex] , then
cos45° = [tex]\frac{1}{\sqrt{2} }[/tex] = [tex]\frac{\sqrt{2} }{2}[/tex] if the denominator is rationalised
