+118658 How do you know that sin45º is √2/2?
Start by drawing a right angled isosceles triangle. Let the legs be one unit long.
Use the Pythagorean theorem to get the length of the hypotenuse.
\(sin45^0=\frac{opp}{hyp}=\frac{1}{\sqrt2}=\frac{1}{\sqrt2}\times\frac{\sqrt2}{\sqrt2}=\frac{\sqrt2}{2}\)
I have never memorised any of the 30,60,45 degree trig ratios, I have only memorised the triangles that are used to work them out. That is my preference, not everyone's :)
