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 ` ` ` ` ` ` ` ` ` ` ` `
What is the position of T with respect to O?
What is the sum of present age of C and the one who is third to the right of C?
Which of the following statement is/are true?
I) T sits second to the right of W
II) Only one person sits between V and Y when counte...
How many persons sit between the one who sits to the immediate right of U and the one who sits to the immediate right of R?
Which of the following statements is/are not true regarding I?
Six friends (R, S, T, U, V and W) are sitting around a circle facing the center. Two friends sit between R and T. U sit second to the right of R and sit...
How many persons sit between D and V, if counted from the right of V?
In which of the following statement, the first and second persons are sitting opposite to each other in the final arrangement?
I) PW
...
Which of the following numbers will replace the question mark (?) in the given series?
5, 10, 30, 120, ?, 4320
Eight people are sitting around a circular table facing the centre. T is sitting between O and D. D is sitting third to the right of R. Z sits between ...
