Cos(a+b)=0.8 Sin(a-b)5/13 and find Tan2a

Question

Sunil Raikwar · Answer

sin2a=sin{(a+b)+(a-b)}=sin(a+b)cos(a-b)+cos(a+b)sin(a-b) =3/5.12/13+4/5.5/13 =56/65 tan2a=56/33 Thanks & Regards Sunil Raikwar askIITians Faculty

siddharth gupta · Answer

cos(a+b)=4/5i.e cos -1 4/5=a+b i.e tan -1 3/4=a+b(can be calculated by considering a right triangle)......(1) similarly sin -1 5/13=a-b and hence tan -1 5/12=a-b(calculated as above)......(2) add (1)and(2) a+b+a-b=2a=tan -1 5/13+tan -1 5/12=tan -1 56/33i.e tan2a=56/33. thanks siddharth gupta

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Cos(a+b)=0.8 Sin(a-b)5/13 and find Tan2a

Cos(a+b)=0.8 Sin(a-b)5/13 and find Tan2a

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