SOLUTION: Given that y = x + cosx , find dy/dx and the approximate change in y when x increases from π/6 to π/5.

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Question 1192775: Given that y = x + cosx , find dy/dx and the approximate change in y when x increases from π/6 to π/5.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
You didn't mention how to get there so I'll be straightforward.
y=x%2Bcos%28x%29
dy%2Fdx=1-sin%28x%29
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Approximate change? Why not exact change in y?
y%5B2%5D=pi%2F5%2Bcos%28pi%2F5%29
y%5B1%5D=pi%2F6%2Bcos%28pi%2F6%29
So the change in y would be,
y%5B2%5D-y%5B1%5D=pi%2F5%2Bcos%28pi%2F5%29-%28pi%2F6%2Bcos%28pi%2F6%29%29
y%5B2%5D-y%5B1%5D=pi%2F5-pi%2F6%2Bcos%28pi%2F5%29-cos%28pi%2F6%29
Approximate from there.