The best way for him to check his answer would be to simply plug in the value found for x into the equation.
4(2) - 6 = 2
8 - 6 = 2
2 = 2
Answer:
C
Step-by-step explanation:
Answer:
1.) 15
2.) -21
3.) -15
4.) 21
Step-by-step explanation:
F(x) = cos x
f'(x) = -sin x
f''(x) = -cos x
f'''(x) = sin x
f''''(x) = cos x
90/4 = 22 Remainder 2
Therefore, 90th derivative of f(x) = cos x is -cos x.
