Question
If (x24Â +Â 1)/x12Â = 7, then
the value of (x72Â +Â 1)/x36Â isÂSolution
(x24 + 1)/x12 = 7 ⇒ x24/x12  + 1/x12  = 7 ⇒ x12 + 1/x12   = 7 ∴ (x72 + 1)/x36 = x72/x36 + 1/x36   = x36 + 1/x36   =  (x12 + 1/x12 )3 – 3 × x12 × 1/x12  (x12 + 1/x12)  ∵ (a + b)³ = a³ + b³ + 3ab (a + b) = 7³ - 3 × 7 = 343 – 21 = 322
A man can row a boat in still water at a speed of 8 km/h. He rows downstream for 1 hour and then returns upstream. If the total time taken for the entir...
- What is the term for restarting a computer that is already powered on?
{14.13 x 28.84 - 39.95% of 420.09 + 128.89} = ?
A coin is tossed. If head occurs, a ball is drawn from a bag containing 3 red and 4 green balls. If tail occurs, a die is thrown. The probability that t...
If a, b, c are in GP, then which of the following is always true ?
Solve the quadratic equations and determine the relation between x and y:Â
Equation 1: x² + 2x - 15 = 0
Equation 2: y² - 4y - 12 = 0
A man observes the top of a tower at an angle of elevation of 45°. He walks 50 meters towards the tower, and the angle of elevation becomes 60°. What ...
Simplify: (1 + i)³ / (1 + i³)
Let sinA+ sinB = a and cosA+ cosB = b, then the value of a² + b² = ?
A particular sum of money, when invested at a simple interest rate, yields Rs. 3,000 as interest after 2 years. The same sum, whe...
