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Vr+ Vy, tan Vx + tan Vy, -1, 1-, Vay, 3x-x), 6. tan, 2x, -1, (3x-x), tan, 8. tan x+ tan, 1-x, 1-3r, 7. 3tan r= tan, (1-3r, 9. cos (1-2r)= 2sin 'x 10. cos (2x-1)=2cosr, 2, %3D, 11. Prove that:, -13, -1, + tan, (ii) tan, 7., + tan-, tan-l, 1, (i) tan, 14, 11, -1, TC, (iii) tan 2- tan 1 = tan", (iv) tan 1+ tan, -1, + tan, 2, 1, TC, -1, -1, - tan, 19, (vi) tan, -1, + tan, 8 4, (v) tan, + tan, %3D, %3D, tan3, 2, [CBSE 2011, '12C], 17, 8., +sin, -1, = COS, (36, (vii) sin, [CBSE 2012], 85, (56, = sin, 65, -1, (viii) cos, -1, +sin, 13, [CBSE 2012], 12. Prove that:, (i) 2tan + tan, 31, -1, = tan, -1, (ii) 2tan1, 3, + tan, 17, -12, (iii) tan + tan, 4, tan, 3, (iv) tan 1+ cos, 9 2, +sin, -1, 3n, 4, 4, 12, [CBSE 2007], (v) cos"즈., 33, = COS, + cos, -1, 13, 65, [CBSE 2009C], 13. Write cot (V1 +x -x) in the simplest form., 14. Find the value of tan, x-y, [CBSE 2007], -1x, -1, tan, (x+y), [CBSE 2011], ANSWERS (EXERCISE 4B), (iv), 2, 3, 2. (i), -o (iv ( (v) (vi) 1 (vii)0, (iii), 5, (i) (ii), 3., V3, TC, 13., 1., 2 cotr, 14., HINTS TO SOME SELECTED OU, 1/3110, II, 1/7112N, 1/2115, 1,, 868, 11/3, 315 5, 117, 3/4, 1,