wat has to be done??
proof??
both are diff questions or same question??
Asked by krish1092
2cos9xcos7x=2cos5xcos3x and
2sin5xcos3x=2sin9xcos7x
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4 Answers
Lokesh Verma
·2008-11-02 22:14:53
sovle.. get the values of x for which these individual identities hold
Lokesh Verma
·2008-11-02 22:41:10
1) cos8x=-1
2) sin8x=0 or cos8x=1/2
these are fairly simple to reach... just use the sum and difference formula!
After this these are standard identities to solve :)