Question

the length of a book is 17.8±0.8cm and breadth is 12.4±0.04cm. calculate the percentage error in these area​

Answer 1

Answer:

The correct answer is 4.29.

Step-by-step explanation:

It is given in the problem that Length of a sheet is 17.3 +/- 0.3 cm and breadth is 3.12 +/- 0.08 cm.

Error in the length= 0.3cm

Length of a sheet= 17.3 cm

Error in the breadth= 0.08 cm

Breadth of a sheet= 3.12 cm

Calculate the percentage error in the area.

Here, L and B are the length and breadth.  and  are the change in the length and breadth.

Put , , L= 17.3 cm and B= 3.12 cm.

Therefore, the percentage error in the area is 4.29.

Answer 2

Answer:

This implies that

x2+2ax=4x−4a−13

or

x2+2ax−4x+4a+13=0

or

x2+(2a−4)x+(4a+13)=0

Since the equation has just one solution instead of the usual two distinct solutions, then the two solutions must be same i.e. discriminant = 0.

Hence we get that

(2a−4)2=4⋅1⋅(4a+13)

or

4a2−16a+16=16a+52

or

4a2−32a−36=0

or

a2−8a−9=0

or

(a−9)(a+1)=0

So the values of a are −1 and 9.