Answer

Step by step solution by experts to help you in doubt clearance & scoring excellent marks in exams.

Updated On: 17-4-2021

Apne doubts clear karein ab Whatsapp par bhi. Try it now.

CLICK HERE

Loading DoubtNut Solution for you

Watch 1000+ concepts & tricky questions explained!

6.8 K+

300+

Transcript

Time | Transcript |
---|---|

00:00 - 00:59 | we need to prove that two caused by 13 into cos 9513 + cos 3 pi by 13 + cos 55 13 is equal to zero so he will take any question that is to Cos pi by 13 into cos 9 by 13 + cos 30 + cos 55 by 32 first of all we will use the identity or in this part 2 using 2 cos a cos b know what is 2 cos a cos b b is equal to Cos A + B + cos and we have we will take the bigger value as a and b bye-bye 30 |

01:00 - 01:59 | so by using identity this will be equal to that is 9513 + 13 + cos a minus b that is 9 pie by 13 - 13 + cos 3 pi by 30 + cos x by 13 so this will be equal to cos 10 cos 30 + cos 30 + cos 3 pi by 13 + cos 55 by 13 now we will group together pair of tools will group together cos10 PB 13 the biggest value with the smallest value that is cos 3 pi by 13 and the next player will be cause |

02:00 - 02:59 | 13 + cos 55 B 32 using identity of Cos A + cos B cos A + cos B this is equal to twice Cos A + B upon 2 into Cos A minus b upon 2 first you will use date in the first bracket to this will be twice in call A + B by 2 Te 10 13 + 3:30 upon 2 into cos tan pi by 13 - 313 upon 2 |

03:00 - 03:59 | second bracket again the same identity that will be to into Cos A + B that it 13 + 5.30 divided by 2 into cos 13 - 5513 upon to sunao evaluating the values this will be to into cos 10 plus 3 that is 1313 upon 2 into cos 10 - 3 that is 713 upon 2 + 2 cos 85 that is again 13 by 13 upon 2 into cos 8th - 5 that is 313 upon 2 |

04:00 - 04:59 | now now solving it further this will be 13 will cancel out 13 to this will be to cause by 2 into cos this will be 7526 plus this will be 2 Cos pi by 2 3 pi by 26 now taking to cause fibre to common on both the bracket should we will be left with call 726 + cos 3 pi by 26 now we know the value of Cos pi by 2 that is cos 90 degree that is equal to zero by 2 is equal to zero so this will be equal to 2 into |

05:00 - 05:59 | Hero cos 75 by 26 + cos 3 pi by 26 so this will be equal to zero and that is equal to RHS and hence proved |