Expression denotes a `value', where a `method group' was expected

Unity Engine
1

public float SplineBlend(int k, int t, int[ ] u, float v)
{
float rvalue = 0;

if (t == 1)
{
if ((u[k] <= v)(v < u[k + 1]))

I get the above error at the last line.
Many thanks in advance.

2

That isnt a valid boolean expression
Fix your brackets, or add some boolean operators
for example
if ( (u[k] <= v) && (v < u[k + 1]) ) {…}