1tan(2a)=tan(a+b+a-b)
= tan(a+b)+ tan(a-b)/1-tan(a+b)tan(a-b)
find value of tan(a+b) and tan(a-b)
ans is -63/16
cos(a+b)=4/5 &cps(a-b)=5/13 & a,b lies in b/w 0o to 45o ,find the value of tan2a.
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2 Answers
1
1sin { a + b } = 3 / 5
Hence , tan { a + b } = 3 / 4 ...................... [ these can be easily found out ]
sin { a - b } = 12 / 13
Hence , tan { a - b } = 12 / 5 ..................... [ proceeding in the similar way ]
So , tan { 2 a } = tan { a + b + a - b }
= tan [ { a + b } + { a - b } ]
= tan { a + b } + tan { a - b }1 - tan { a + b } tan { a - b }
= 3 / 4 + 12 / 51 - { 36 / 20 }
= - 6316