Question #9c033
1 Answer
Jan 5, 2018
Explanation:
#"using the "color(blue)"trigonometric identities"#
#•color(white)(x)tanx=sinx/cosx#
#•color(white)(x)sin^2x+cos^2x=1#
#rArr(cancel(cosb)xxsinb/cancel(cosb)+1)(sinb-1)#
#=(sinb+1)(sinb-1)#
#=sin^2b-1#
#"take out a common factor of "-1#
#=-(1-sin^2b)=-cos^2b#