how to using atan2

hello

i want to using 'atan2' function.

but it's hard to found out error for program.

if theta2 and theta 4 is fondated, i want to find according theta3

please help how can use atan2 thanks.

[Les Beckham]

If you want to use 'atan2', you should call 'atan2' instead of 'atna2'.

Also, the first error message is pretty clear. You have not defined 'l1'.

In the future I recommend copying and pasting text into your questions instead of using screenshots (images). This makes it easier for those that are trying to help you to copy to copy and run your code and to see the entire contents of error messages.

[Walter Roberson]

Also calling a function uses () brackets not [] brackets

atan2(y, x)