Is sorted array using recursion?

Since, recursion works one case less than the actual case. So, in this case if i assume ki 1st element already sorted hai. So mujhe kya yeh check krna hoga ki remaining elements sorted hai ya nhi ?? For example- the array is 10,20,30,90,80
toh es array mei agr mei assume krta hu ki mera 1st element already sorted hai…toh mujhe recursion remaining elements pr lgna hoga kya ???