I am unsure where to begin with finding this partial derivative.
f(x,y)=integral from y to x of cos(t^2)dt
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Using the Fundamental Theorem of Calculus and noting that y is treated as a constant when you differentiate with respect to x:
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Now note that and use the Fundamental Theorem of Calculus again (note that x is treated as a constant when you differentiate with respect to y):
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