find algebraically, the absolute extrema of y=sinx+cosx in the interval [0,2pie].?

Answer 1

Hello

y' = cosx - sinx now set it = 0 to find max or min 0 = cosx - sinx and then cosx = sinx so sinx/cosx = 0 or tanx and this happens at 0, pi, 2pi. Put these back onto the original equation to see what happens.

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