Why walk \$-sec(x)\$ become positive \$1/cos(x)\$?I thought that the an unfavorable would carry and it would be \$-1/cos(x)\$.

You are watching: Secx-1/1-cosx=secx  You space right. Just by looking in ~ the an interpretation of \$sec(x)\$, one can plainly see that \$\$sec (x) = frac1cos (x)\$\$

But don"t just take my word because that it. Your equation itself will certainly tell friend if it"s appropriate or wrong.

\$\$ -sec (x) = frac1cos (x) implies -frac1cos (x) = frac1cos (x) implies large-1 =1 implies extFalse\$\$Now, over there is a result similar come this which is true,\$\$ sec (-x) = frac1cos(-x) = frac1cos(x)\$\$

Why did the happen? due to the fact that \$ cos(-x) = cos(x)\$.

Again don"t simply take mine word for it. I have the right to prove it making use of the identification \$cos(A pm B) = cos(A) imescos(B) mp sin(A) imessin(B)\$.\$\$cos(-x) = cos (0-x) = cos 0 imescos x + sin 0 imessin x = 1 imescos x + 0 imessin x = cos x\$\$Never confuse \$sec(-x)\$ through \$-sec(x)\$. Constantly remember that\$\$ sec(-x) = +sec(x) quadforall xin ememberingsomer.combbR \$\$

\$ddotsmile\$ hope this help

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edited Mar 3 "14 in ~ 22:42
answer Mar 3 "14 in ~ 22:35 NickNick
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