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What exactly are you struggling with in these questions? Which step of the question do you get stuck on
Theorems
You could do this but it does not demonstrate understanding of chain rule.Just remember these:
y = sin [ f(x) ]
y' = f'(x) x cos [ f(x) ]
y = cos [ f(x) ]
y' = f'(x) x -sin [ f(x) ]
y = tan [ f(x) ]
y' = f'(x) x sec^2 [ f(x) ]
Let's apply this to the question above:
y = sin [ 1/4x + pi/2 ]
So f(x) = 1/4x + pi/2
f'(x) = 1/4
Therefore y' = 1/4 x cos [ 1/4x + pi/2 ]
But the question is asking for y'(pi)
So in place of x, we now substitute x = pi
Doing this we get y'(pi) = 1/4 x cos [ 1/4(pi) + pi/2 ] = ________
You can take it step by step until you reach your answer, don't get overwhelmed![]()
The problem is that the answer i get is different to the answer in the text book