Using constraint method find the relation between of `a_(1)` and `a_ (2)`.

Explanation

In fig `8.84` points `1,2,3` and `4` are movable . Let their displacements from a fixed dotted line be `x_(1),x_(2),x_(3)`and `x_(4)`
`x_(1)+x_(3)=l_(1)`
`(x_(1)-x_(3))+(x_(4)-x_(3))=l_(2)`
`(x_(1)-x_(4))+(x_(2)-x_(4))=l_(3)`
On double differentiating with respect to time, we will get following three constraint relations
`a_(1)+a_(3)=0 ` ...(i)
`a_(1) + a_(4) - 2a_(3) = 0 ` ...(ii)
`a_(1) + a_(2) - 2a_(4) = 0 ` ...(iii)
Solving Eqs. `(i),(ii)` and `(iii)`, we get
`a_(2) = - 7a_(1)`
Which is the desired ralation between `a_(1)` and `a_(2)`.