It's dependent on the context. A book may ask you to find the f'(x) of a function and you may have to use a u sub in your problem which requires you to find the dy/dx of what you substitute. So in this case both would be used.
1-1, 1-2, 1-3, 1-4 and u should Change it to middle school
Answer:
5 radical 3
Step-by-step explanation:
b = √c2 - a2
= √102 - 52
= √75
= 8.66025 = 5√3