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Grade 10Trigonometry

if 420(tanA+cotA)=841 then what is value of (116cosA - 58sinA)

Profile image of Matt Farrel
12 Years agoGrade 10
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1 Answer

Profile image of Arun Kumar
ApprovedApproved Tutor Answer12 Years ago
Hello Student,
420(tanA+cotA)=841
420(sinA/cosA +cosA/sinA) =841
420/sinAcosA=841
sin2A=840/841
cos2A=sqrt of (1681/841^2)=41/841
cosA=sqrt of (1+cos2A)/2=21/29
sinA=sqrt of (1-cos2A)/2=20/29
116cosA-58sinA=116(21/29)-58(20/29)=44
Thanks & Regards
Arun Kumar
Btech, IIT Delhi
Askiitians Faculty