1. Let =2+3k,b=++k and c be a vector such that + (bc)=0 and .c=5. Then, the value of 3(c.a) is equal to............ 2. Let y y(x), x>1, be the solution of the differential equation (x-1) dy dx 1 x-1 +2xy= ,with y (2)= 1+e4 2e4 If y(3) = e +1 Be then the value of a + is equal 3. to........ Let 3, 6, 9, 12,.... upto 78 terms and 5, 9, 13, 17,.... upto 59 terms be two series. Then, the sum of the terms common to both the series is equal to.............. 4. The number of solutions of the equation sin x = cos x in the interval (0, 10) is............