Question
in triangle ABC,right-angled at A,if cot B=1, find the value of cosB cosA+sinB sinC
Answers
Steve
cotB=1 so B=pi/4, so C=pi/4
cosA = 0
sinB = sinC = 1/√2
. . .
cosA = 0
sinB = sinC = 1/√2
. . .