7
AssignmentMultiple Choice

Differentiating Trigonometric Functions

Question 7 • AP Calculus AB - MA5186 A

What is the derivative of y = sin x + cos x?

Answer
A
y′ = sin x + cos x
B
y′ = sin x − cos x
C
y′ = cos x – sin x
D
y′ = −cos x − sin x

Explanation

Differentiate each term separately: the derivative of sin x is cos x, and the derivative of cos x is −sin x. Therefore, y′ = cos x − sin x, which is choice C.

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