Expert: Sherry Wallin - 4/20/2009

Question
QUESTION: "all x's stand for theta

(1+sinx)(1-sinx)(secx+1)(secx+1)

[sinx-(sinx)(cosx)]/1-cosx

2sinx/1-cos^2(x)

[sin^2(x)/cos^2x] +sinx times cscx=sec^2(x)

[cosx/sinxcotx]/1

1-secxcosx=tanxcotx-1

[1/tanx-secx]  + [1/tanx+secx]=-2tanx

cosx ( tan^2x+10)=secx

sec^2xcotx-cotx=tanx

sin^3x+sinxcos^2x=sinx

cot^2x-cos^2x=cot^2x times cos^2x

ANSWER: Kate, what is the question?

Math Prof

---------- FOLLOW-UP ----------

QUESTION: Can you actually help me solve these two problems :
[sin^2(A)/tan^2] + sin^2(A)

Answer
Kate~
    The problem is, there is no problem. If you were to say for example that you need to show 1-secxcosx=tanxcotx-1 is an identity then I could show you. You have given me [sin^2(A)/tan^2] + sin^2(A). What is it you want to know about that expression? Are you wanting to know what else it is equal to? Notice there is no equal sign in what you gave me, so I can't show an identity with an expression, you can only show an identity with an equation,which means quite literally that you need an equal sign. I will show you an expression it is equal to.

[sin^2(A)/tan^2] + sin^2(A)= {[sin^2(A)]/1}/[sin^2(A)/cos^2(A)]+sin^2(A)
= cos^2(A) + sin^2(A) = 1

If you need to show identities then for these problems (from above):

1-secxcosx=tanxcotx-1

[1/tanx-secx]  + [1/tanx+secx] = -2tanx

cosx ( tan^2x+10)=secx

sec^2xcotx-cotx=tanx

sin^3x+sinxcos^2x=sinx

cot^2x-cos^2x=cot^2x times cos^2x

you can show if they are identities but then you need to state that is what is wanted. The others above these are just expressions and you can only simplify.

Math Prof