Question
sin2 17˚ + sin2 19˚ +
sin2 21˚ + sin2 23˚ + ……… + sin2 77˚ = ?Solution
sin 2 17˚ + sin 2 19˚ + sin 2 21˚ + sin 2 23˚ + ……… + sin 2 77˚ = (sin2 17˚ + sin2 73˚) + (sin2 19˚ + sin2 71˚) + .…. + (sin2 43˚ + sin2 47˚) + sin2 45˚ = (sin2 17˚ + cos2 17˚) + (sin2 19˚ + cos2 19˚) + .…. + (sin2 43˚ + cos2 43˚) + sin2 45˚ {As sin (90˚ - θ) = cos θ} = (1)+(1) + .…. upto 14 times + sin2 45˚ { As sin 2 θ + cos 2 θ= 1} = 14 + sin2 45˚ {As there are 14 odd numbers from 14 to 43}. = 14 + (1/√2)2 {As sin 45˚ =1/√2 } = 14 + 0.5 = 14.5 ` ` ` ` ` ` ` ` ` ` ` `
If P means ‘multiplied by’, T means ‘subtracted from’, M means ‘added to’ and B means ‘divided by’, then 40 B 8 P 8 T 14 M 9 = ?
...If ‘+’ means ‘–’, ‘–’ means ‘÷’, ‘÷’ means ‘×’, and ‘×’ means ‘+’, what will come in place of the question mar...
Select the correct combination of mathematical signs that can sequentially replace '*' sign and balance the equation given below.
86 * (38 * 1...
Select the correct combination of mathematical signs that can sequentially replace the * signs and balance the given equation.
56 * 492 * 6 * 7 * 123 = 507
If ‘A’ means ‘divided by’, ‘B’ means ‘multiplied by’, ‘C’ means ‘added by’ and ‘D’ means ‘subtracted from’, than – 105...
The given equation has been solved on the basis of a certain rule. Find the correct answer for the unsolved equation on that basis:
If a ÷...
Select the correct combination of mathematical signs that can sequentially replace the * signs and balance the given equation.
60 * 48 * 36 * 6 * 15 * 53
Which one of the given mathematical operations will result in 291?
If ‘A’ means (÷), ‘B’ means (×), ‘C’ means (+), and ‘D’ means (-), then ____ is the value of the expression.
25 A 5 B 8 D 6 C 4...
Select the correct combination of mathematical signs to replace the '*' signs and to balance the given equation.
169 * 13 * 30 * 12 * 4 * 18 = 85
