Question

If the coordinates of vertices of AOAB are (0,0) (cosa, sina) and (-sina, cosa) respectively, then OA2 + OB2 =
?????​

Answer 1

Answer:

A=1 and OB=1 ∴

AB= √2∴(cosβ−cosα)2(sinβ−sinα)2 =2

⟹cos 2α+sin 2α+cos2 β+sin

2

β−2sinβsinα−2cosβcosα=2

⟹2sinβsinα+2cosβcosα=0

∴cos(α−β)=0

⟹sin( 2α−β )/2=± 1/√2

⟹cos( 2α−β)/2=± 1/√2