Answers

2014-09-09T10:50:41+05:30
squaring on both sides
sin²2A+cos²2A+2sinAcosA=289/169
1+2sinAcosA=289/169
2sinAcosA=289/169-1
2sinAcosA=120/169
sinAcosA=60/169
now
sinA-cosA=root(sinA-cosA)²
sinA-cosA=root(sin²2A+cos²2A-2sinAcosA)
sinA-cosA=root(1-2SinacosA)
sinA-cosA=root(1-2*60/169)
sinA-cosA=root(49/169)
sinA-cosA=7/13
hence the answer of sinA-cosA=7/13
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