Download App

Identities — MATHS STD 8 — Question

ICSE BoardEnglish MediumSTD 8MATHSIdentities4 Marks
Question
Find the square of $2 a-\frac{1}{a}$
✓

Answer

$ \left(2 \mathrm{a}-\frac{1}{\mathrm{a}}\right)^2$
$=(2 \mathrm{a})^2+\left(\frac{1}{\mathrm{a}}\right)^2-2 \times 2 \mathrm{a} \times \frac{1}{\mathrm{a}}$
$ =4 \mathrm{a}^2+\frac{1}{\mathrm{a}^2}-4$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "[4 marks sum]" from Identities→Identities — all question types→MATHS STD 8 question papers→ICSE Board STD 8 question papers→ICSE Board question paper generator→

Similar questions

If $a^2 + b^2 = 29$ and $ab = 10$, find :$ a − b$
→
The perimeter of a rhombus is $40\  cm$. If one diagonal is $16\  cm$ ; find : It's other $(i)$ diagonal $(ii)$ area
→
Divide $Rs. 15,600$ into two parts such that the interest on one at $5$ percent for $5$ years may be equal to that on the other at $4 \frac{1}{2}$ percent for $6$ years.
→
Expand : $(x + 5y)^3$
→
Solve the following equation : $3 a-\frac{1}{5}=\frac{a}{5}+5 \frac{2}{5}$
→
A shop$-$keeper bought rice worth $Rs.4,500.$ He sold one$-$third of it at $10\%$ profit.If he desires a profit of $12\%$ on the whole; find $:(i)$ the selling price of the rest of the rice $;(ii)$ the percentage profit on the rest of the rice.
→
$A$ and $B$  working together can mow a field in $56$ days and with the help of $C$, they could have mowed it in $42$ days. How long would $C$ take by himself?
→
For each set of rational number, given below, verify the associative property of addition of rational number: $(i)$ $-1, \frac{5}{6}$ and $\frac{-2}{3}$
→
Divide $x^6 – y^6$ by the product of $x^2 + xy + y^2$ and $x – y.$
→
For the following inequation, represent the solution on a number line : $\frac{4-x}{2}<3, x \in R$
→