If a + b = \(\frac{3}{4}\) and ab = \(\frac{1}{8}\), then
find a4 + b4 + ab3 + ba3.
Answer & explanation
Correct answer: option 3
a + b = \(\frac{3}{4}\)
Squaring both sides
a2 + b2 + 2ab = \(\frac{9}{16}\)
a2 + b2 = \(\frac{9}{16}\) - 2 × \(\frac{1}{8}\)
a2 + b2 = \(\frac{5}{16}\)
Squaring both sides again in equation
a4 + b4 = \(\frac{25}{256}\) - 2a2b2
a4 + b4 = \(\frac{25}{256}\) - 2 × \(\frac{1}{64}\)
a4 + b4 = \(\frac{17}{256}\)
⇒ Put the value in below equation
⇒ a4 + b4 + ab (a2 + b2) = \(\frac{17}{256}\) + \(\frac{5}{128}\) = \(\frac{27}{256}\)