Question

if x= sinx +cosx find dy/dx at x= pie/4

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Answer 1

$GOOD \: MORNING \: \\ \\ y = \sin(x) + \cos(x) \\ \\ dy \div dx = d( \sin(x) ) \div dx \: + \: d( \cos(x)) \div dx \\ \\ dy \div dx = \cos(x) - \sin(x) \\ \\ at \: = 45 \\ \\ dy \div dx = (1 \div \sqrt{2} ) - (1 \div \sqrt{2} ) \\ \\ dy \div dx = 0$