A) \[-\,1\]
B) 1
C) 0
D) none of these
Correct Answer: B
Solution :
| Note that \[\cos 158{}^\circ =\cos \,\,(180{}^\circ -22{}^\circ )=-\cos 22{}^\circ \] & \[\cos 98{}^\circ =\cos \,\,(90{}^\circ +8{}^\circ )=-\,\sin 8{}^\circ \] |
| Also \[\cos 157{}^\circ =\cos (180{}^\circ -23{}^\circ )\] |
| \[=-\,\cos 23{}^\circ \] |
| & \[\cos 97{}^\circ =\cos (90{}^\circ +7{}^\circ )=-\,\sin 7{}^\circ \] |
| \[\therefore \] Given expression |
| \[=\frac{\sin 22{}^\circ \cos 8{}^\circ +\cos 22{}^\circ \sin 8{}^\circ }{\sin 23{}^\circ \cos 7{}^\circ +\cos 23{}^\circ \sin 7{}^\circ }\] |
| \[=\frac{\sin (23{}^\circ +8{}^\circ )}{\sin (23{}^\circ +7{}^\circ )}=1\] |
| \[\therefore \] Ans. is B |
You need to login to perform this action.
You will be redirected in
3 sec
