velocity of piston

The instantaneous configuration of a slider crank mechanism has a crank GH 10cm long, the connecting rod HP is 50cm. The crank makes an angle of 60 degree with the inner dead centre position and is rotating at 110 rev/min. Determine the velocity of the piston P and the angular velocity of the link HP.
Here is the diagram

my guess would be to use this formula [ -rw(cos(60)+((sin2(60)/(2xsqrt(n²-sin²(6…‡ ]
where n = L/R
but i get a negative answer which seems a bit low.
can someone give me steps on how to complete this question correctly? because i aim to revise from it for my exam thank you

Attachment 23600

find b from cosine rule then you can find the instantaneous center. From that you can find the answer.