Pertanyaan

Diketahui persegi panjang PQRS seperti pada gambar dengan panjang 5 cm dan lebar 3 cm. Agar luas ABCD mencapai nilai minimum, luas daerah yang diarsir adalah....

A. Acfreelance

Master Teacher

Jawaban terverifikasi

Pembahasan

$M a k a comma space l u a s space y a n g space d i a r s i r space equals 2 cross times open parentheses 1 half x open parentheses 5 minus x close parentheses plus 1 half x open parentheses 3 minus x close parentheses close parentheses space equals 2 cross times 1 half x open parentheses 5 minus x plus 3 minus x close parentheses equals x open parentheses 8 minus 2 x close parentheses equals 8 x minus 2 x squared A g a r space l u a s space A B C D space m i n i m u m comma space m a k a space l u a s space d a e r a h space y a n g space d i a r s i r space h a r u s l a h space m a k s i m u m space d a n space d a p a t space d i c a r i space m e n g g u n a k a n space t u r u n a n space p e r t a m a space l u a s space y a n g space d i a r s i r colon fraction numerator d L over denominator d x end fraction equals 0 fraction numerator d L over denominator d x end fraction equals 8 minus 4 x 0 equals 8 minus 4 x 4 x equals 8 x equals 8 over 4 equals 2 S e h i n g g a comma space L equals 8 x minus 2 x squared equals 8 open parentheses 2 close parentheses minus 2 open parentheses 2 close parentheses squared equals 8$