Question

in what time will the compound interest on ₹5120 at 12half 1/2% per annum compounded annually be ₹1360​

Answer 1

Answer:

For solving and finding the cos-1x ,we have to remember below three listed formulae.

limh->0 {f(x + h) – f(x)} / h

cos-1x + sin-1x = pi/2

cos-1x = pi/2 – sin-1x

Now, let’s solve, we have.

f(x) = cos-1x

f(x + h) = cos-1(x + h)

limh->0 {cos-1(x + h ) – cos-1(x)} / h

limh->0 {pi/2 – sin-1(x + h) – (pi/2 – sin-1x) } / h

limh->0 {pi/2 – sin-1(x + h) – pi/2 + sin-1x } / h

Taking – sign common, we get

– limh->0 {sin-1(x + h) – sin-1x} / h

Since we know that limh->0 { sin-1(x + h) – sin-1x } / h = 1 / √(1 – x2)

Putting the value in our solution we get,

– 1 / √(1 – x2)

Answer 2

Ans : 2 years
Principle - 5120
Rate of interest - 12.5 %
No of years - ?
Sol:
12.5 % of 5120 is 640
Two years 1280 rupees
For that 12.5 % of 640 is 80
If u add you will get 1360
Hence the answer is two years check the diagram below