If `(0, 0)` is orthocentre of triangle formed by `A(cosalpha,sinalpha),B(cosbeta,sinbeta),C(cosgamma, singamma)` then `/_BAC` is

(cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2 =

Evaluate triangle = |[0,sinalpha,-cosalpha],[-sinalpha,0,sinbeta],[cosalpha,-sinbeta,0]|

Find |A| if A=[{:(0,sinalpha,cosalpha),(sinalpha,0,sinbeta),(cosalpha,-sinbeta,0):}]

Show without expanding at any stage that: | (1,cosalpha-sinalpha, cosalpha+sinalpha),(1,cosbeta-sinbeta,cosbeta+sinbeta),(1, cosgamma-singamma,cosgamma+singamma)| =2 |(1,cosalpha, sinalpha),(1,cosbeta, sinbeta),(1,cosgamma,singamma)|

Show without expanding at any stage that: | (1,cosalpha-sinalpha, cosalpha+sinalpha),(1,cosbeta-sinbeta,cosbeta+sinbeta),(1, cosgamma-singamma,cosgamma+singamma)| =2 |(1,cosalpha, sinalpha),(1,cosbeta, sinbeta),(1,cosgamma,singamma)|

The distance between the points (a cosalpha, a sinalpha) and (a cosbeta, a sinbeta) where a> 0

The distance between the points (a cosalpha, a sinalpha) and (a cosbeta, a sinbeta) where a> 0

The distance between the points (a cosalpha, a sinalpha) and (a cosbeta, a sinbeta) where a> 0

The distance between the points (a cosalpha, a sinalpha) and (a cosbeta, a sinbeta) where a> 0