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GALACTIC INSTITUTE HARE &_KRISHNA MATHEMATICS-X-10, PRACTICE EXERCISE 3.3, , Q.1 Find the values of the following :, , , , , , , , , , (i) sin 75° (ii) cos 75° iii) sin 15° (iv) cos 15°, ee 1 v3-1 v3-1 ee 1, LO 3+ ws Gin w)> 3+, , Q.2 Prove that :, , , , tan(Z+x) _ (= ), , tan(2—x) ~ \g-tan x, , Q.3 Prove that :, , (i) cos (E+ x) + cos (F-x) = 2cosx, (ii)cos (+ x) - cos (= x) = v2 sinx, sin(x+y) _ tanx+tamy, , .4 Prove that : =, Q4 sin(x-y) tan x-tany, , Q5 Prove that :, (i) tan 3A tan 2A tan A = tan 3A=>tan 2A-tanA, , (ii) cot A cot 2A - cot 2A.cot 3A-cot 3A cot A = 1, (iii) tan 70° = tan 20° + 2 tan 50°, , Q.6 Prove that: (i) sin?6x = sin? 4x = sin 2x sin 10x, (ii) cos*2x - cos? 6x = sin 4x sin 8x, , Q.7 Prove that: sin?(n +1) A - sin? nA= sin(2n+ 1) AsinA, Q8 The value of cos* (E+0}-si [E-°) is, , (a) 500820 (b) 0 (¢) = 7.00820 (d) ;, , , , GALACTIC INSTITUTE : D-94/49 SECOND FLOOR, MAHAVIR ENCLAVE PART-II NEW DELHI Mob.8826181724 Page 5