Tick (✓) the correct answer:

Question:

Tick (✓) the correct answer:

(a + 1)(a − 1)(a2 + 1) = ?

(a) (a4 − 2a2 − 1)

(b) (a4 − a2 − 1)

(c) (a4 − 1)

(d) (a4 + 1)

Solution:

(c) $\left(a^{4}-1\right)$

$(i)(a+1)(a-1)\left(a^{2}+1\right)$

$\Rightarrow\left((a)^{2}-(1)^{2}\right)\left(a^{2}+1\right)$   [according to the formula $a^{2}-b^{2}=(a+b)(a-b)$ ]

$\Rightarrow\left(a^{2}-1\right)\left(a^{2}+1\right)$

$\Rightarrow\left(a^{2}\right)^{2}-\left(1^{2}\right)^{2}$   [according to the formula $a^{2}-b^{2}=(a+b)(a-b)$ ]

$\Rightarrow a^{4}-1$ 

Leave a comment

Close

Click here to get exam-ready with eSaral

For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.

Download Now