Trig Function Question

[markraz]

Hi, Please see purple question mark below. Is there a Trig function to represent this distance? I realize I can just add versin and exsec or subtract cos from secant, but just out of curiosity does this distance have its own unique function?? or is there some other recommended method to calculate this? How would you people calculate this? just curious
Thanks in advance

 

[skeeter]

[MATH]\sin{\theta}\tan{\theta}[/MATH]

 

[markraz]

[MATH]\sin{\theta}\tan{\theta}[/MATH]

thanks appreciate it