Question #08ca1

2 Answers
Feb 14, 2017

LHS=(sec x sin x)/(tan x + cot x)

=(sec x sin x)/(sinx/cosx + cos x/sinx)

=(sec x sin x)/((sin^2x+cos^2x)/(cosxsinx))

=secx*sinx*cosx*sinx

=sin^2x

Feb 14, 2017

see explanation.

Explanation:

Making use of the following color(blue)"trigonometric identities"

color(red)(bar(ul(|color(white)(2/2)color(black)(tanx=sinx/cosx,cotx=cosx/sinx)color(white)(2/2)|)))

"and " color(red)(bar(ul(|color(white)(2/2)color(black)(secx=1/cosx)color(white)(2/2)|)))

"left side "=(secx xx sinx)/(tanx+cotx)

color(white)(xxxxxx)=(sinx/cosx)/(sinx/cosx+cosx/sinx)

color(white)(xxxxxx)=(sinx/cosx)/((sin^2x+cos^2x)/(sinxcosx))

color(white)(xxxxxx)=sinx/cancel(cosx) xx(sinxcancel(cosx))/1

color(white)(xxxxxx)=sin^2x="right side"rArr" verified"