The error 'Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

clear
E=70e6
A= 0.004
L1=3.5
theta1=90
L2=4
theta2=0
L3=5.3151
theta3= atan(3.5/4)*180/pi
L4=L3
theta4=360-theta3
L5=4
theta5=0
L6=3.5
theta6=270
k1=PlaneTrussElementStiffness(E,A,L1,theta1)

[muhammad waseem]

Error in

k1=PlaneTrussElementStiffness(E,A,L1,theta1)

[Walter Roberson]

Duplicates https://www.mathworks.com/matlabcentral/answers/843925-calling-function-error-in-matlab?s_tid=srchtitle