Just check whether each of your cluster nodes (Assuming that 2 node cluster) are running atleast one sql server instance.
You can do this from Cluster administrator on any node.
Suppose you have 2 nodes, Node A And Node B and 2 instances SQL 1 and SQL 2.
If SQL 1 is Running on Node A and SQL2 is ruinning on Node B or vice versa, then the cluster is ACTIVE/ACTIVE.
If both instances are running on one node and the other node is passively waiting for the failover and doing nothing then it is ACTIVE\PASSIVE.
Thank You,
Best Regards,
SQLBuddy