Question

Hey guys! Problem 1D8a... f(x)=ax+b, x>0 ; f(x)=sin2x, x
14 years ago

Answer 1

f'(0)=a=2cos(0)=2
so if a is not =2 it's not differentiable at zero

Answer 2

plus it's not differentiable if it's not continuous, which is the case for b not=0

Answer 3

Ok, just saw a topic below and realized and haven't got to the part when I can calculate f'(0-), so for me it didn't make sense that f'(x)=2cos(2x)... Just gonna move on and tackle it again later! I got the b part nonetheless... Thanks a lot for the help ;)

Answer 4

oh yeah, the chain rule is later in the series but there are questions that require it in the beginning. They should fix that :/

Answer 5

...you could perhaps use a trig formula instead