PART-A Q.1 Find the number of real solution(s) of the equation logx9 – log3x2 = 3. [3] Q.2 Simplify: cos x · sin(y – z) + cos y · sin(z – x) + cos z · sin (x – y) where x, y, z R. [3] Q.3 If logx–3(2x – 3) is a meaningful quantity then find the interval in which x must lie. [3] Q.4 If x = 1 and x = 2 are solutions of the equation x3 + ax2 + bx + c = 0 and a + b = 1, then find the value of b. [3] Q.5 tan = 1 2 + 1 2 + 1 where (0, 2), find the possible value of . [3] 2 + cos12 cos 72 Q.6 Find the exact value of sin 72 + sin12 . [3] Q.7 If the tangent of DAB is expressed as a ratio of positive integers a b in lowest term, then find the value of (a + b). [3] 12 A Q.8 If sin A = 13 . Find the value of tan 2 . [3] Q.9 Let x = (0.15)20. Find the characteristic and mantissa in the logarithm of x, to the base 10. Assume log102 = 0.301 and log103 = 0.477. [3] Q.10 The figure (not drawn to scale) shows a regular octagon ABCDEFGH with diagonal AF = 1. Find the numerical value of the side of the octagon. [3] PART-B cos3 + cot(3 + ) sec( 3) cosec 3 Q.11 Simplify tan2 ( ) sin( 2) . [4] Q.12 Find the sum of the solutions of the equation 2e2x – 5ex + 4 = 0. [4] Q.13 Prove the identity cot A + cosec A 1 = cot A . [4] cot A cosec A +1 2 Q.14 If log (log ( log x)) = log (log ( log y)) = 0 then find the value of (x + y). [5] 1 2 1 Q.15 If log25 = a and log 225 = b, then find the value of log + log in terms of a and b 9 2250 (base of the log is 10 everywhere). [5] Q.16 Prove that the expression sin2 + sin2(120° + ) + sin2(120° – ) remains constant R. Find also the value of the constant. [5] y Q.17 Suppose that x and y are positive numbers for which log9x = log12y = log16(x + y). If the value of x = 2 cos , where (0, 2) find . [6] tan 1 cot Q.18 If tan tan 3 = 3 , find the value of cot cot 3 . [6] 2 3 4 Q.19 Let S = sec 0 + sec + sec + sec + sec and P = tan · tan 2 · tan 4 then prove 5 5 5 5 9 9 9 S + P = 2 2 sin 7 [6] 12