Question #723dc

2 Answers
Jan 19, 2018

Please see below.

Explanation:

.

We have the identity:

#sec^2x=tan^2x+1#

Let's plug this into the numerator and factor the #tanx# out of the denominator:

#(tan^2x+1-1)/(tanx(sin^2x+cos^2x))=tan^2x/(tanx(sin^2x+cos^2x))=#

#tanx/(sin^2x+cos^2x)#

But we know:

#sin^2x+cos^2x=1#

Therefore,

#tanx/(sin^2x+cos^2x)=tanx/1=tanx#

Jan 19, 2018

#"see explanation"#

Explanation:

#"using the "color(blue)"trigonometric identities"#

#•color(white)(x)tan^2x+1=sec^2xrArrtan^2x=sec^2x-1#

#•color(white)(x)sin^2x+cos^2x=1#

#"consider the left hand side"#

#((sec^2x-1))/(tanxsin^2x+tanxcos^2x)#

#=(tan^2x)/(tanx(sin^2x+cos^2x))#

#=tan^2x/tanx#

#=tanx=" right hand side "rArr"verified"#