7.19VALUES OF TRIGONOMETRİC FUNCTIONS AT SUMS OR DFFERENCE OF ANGLESEXERCISE 7.1LEVEL-1A-4 and cos B-, where 0 < A, B. find the values of the following:13(ii) cos(A+B)(iii)sin (A-B)2. (a) lfsin A·2 and sin B-4 , where x </: π and0c B <) sin (A B)(iv) cos (A-B), find the followin(ii) cos (A+ B(1) sin (4 +B)t) sin A-1, where A and B both le n second quadrant,find the valueof sin (A t B)INCERT. Ifcors A。一2, and os 8-5, where π«A<3x and 2<b<2n, find the following:4. Iftan A-3, cos B-41, where π < A<3xand 0 < B <프,find tan (A + B).s lf ein A-1, or, B213 , where 2 < A < π and 3: < B < 2, find tan (A-B).6. lisin A-1, dos B--', where , <Acπ and 0 < B < π ' find the following :(ii) cos (A +(i) tan (A+B)(ii)tan (A-B)7. Evaluate the following(ii) cos 47 cos 13 - sin 47 sin 13(iv) cos 80 cos 20+ sin 80° sin 20(i) sin78° cos 18"-cos 78° sin 18"(iii) sin 36° cos 9° + cos 36" sin 9。and cot B 2, where A lies in the second quadrant and B in the thirdquadrant, find the values of the following(iii)(i) sin (A +B) (ii) cos (A + B)9. Prove that: cos 12 + cos 12-sin 12tan A -tan Btan (A+ B)10.Prove that: tan 4 + tan Bsin (A -B)11. Prove that:cos 11° + sin 11°cos 11°-sin 11cos 8。.. sin 80= tan 37。cos 9° +sin 9° = tan 54°cos 90-sin 9。(ii) so in so 3712. Prove that:(iii) sin/3x-5las/프+5.cos(3x-5|sinl2.5|-113. Prove that: tan 69+ tan