Jika r(x)=xcosx, maka r'(x+π/2)
Matematika
AmeliaM99
Pertanyaan
Jika r(x)=xcosx, maka r'(x+π/2)
1 Jawaban
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1. Jawaban ahreumlim
r(x) = x cosx
r '(x) = -x sinx + cosx
r'(x+π/2)
= - (x+π/2) sin(x+π/2) + cos(x+π/2)
= - (x+π/2) [sinx cosπ/2 + cosx sinπ/2] + [cosx cosπ/2 - sinx sinπ/2]
= - (x+π/2) [0 + cosx] + [0 - sinx]
= -(x+π/2) cosx - sinx