can show mi the step...thanx

if sin x=-0.6 and tan x = -0.75,then sec x is

1)-1.25

2)1.25

3)0.80

4)-1.35

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- May 11th 2006, 06:12 AMcheesepieneed help very urgent
can show mi the step...thanx

if sin x=-0.6 and tan x = -0.75,then sec x is

1)-1.25

2)1.25

3)0.80

4)-1.35 - May 11th 2006, 06:23 AMearbothQuote:

Originally Posted by**cheesepie**

1. You know that $\displaystyle \tan(x)=\frac{\sin(x)}{\cos(x)}$ and

$\displaystyle \sec(x)=\frac{1}{\cos(x)}$ so

$\displaystyle \sec(x)=\frac{\tan(x)}{\sin(x)}$

Therefore: $\displaystyle \frac{-\frac{3}{4}}{-\frac{3}{5}}=\frac{5}{4}$

Thus the answer is 2)

Greetings

EB - May 11th 2006, 06:24 AMCaptainBlackQuote:

Originally Posted by**cheesepie**

so:

$\displaystyle

\sec(x)=\tan(x)/\sin(x)=(-0.75)/(-0.6)=1.25

$

RonL - May 11th 2006, 06:35 AMearbothQuote:

Originally Posted by**CaptainBlack**

I'm a little bit confused, because I read a sin x = -0.6 in the problem of cheesepie.

Greetings

EB - May 11th 2006, 07:09 AMcheesepie
can u show mi the step of this question ? thanx

if cos x=0.6 and tan x is negative ,then csc x is

1)1.25

2)-1.25

3)0.80

4)0.75 - May 11th 2006, 08:07 AMCaptainBlackQuote:

Originally Posted by**earboth**

RonL - May 11th 2006, 12:37 PMearbothQuote:

Originally Posted by**cheesepie**

This problem is a tricky one, because you didn't give a value for tan(x). To be able to calculate a value I take the value from the previous problem: tan(x)=-.75

1. You know that $\displaystyle \cot(x)={\cos(x) \over \sin(x)}$ and

$\displaystyle \csc(x)={1 \over \sin(x)}$ and $\displaystyle \tan(x)={\sin(x) \over \cos(x)}$ So you get:

$\displaystyle \csc(x)={{\cos(x) \over \sin(x)} \over \cos(x)}}$ = $\displaystyle {{1 \over \tan(x)} \over \cos(x)}}$ = $\displaystyle {{1 \over -.75} \over .6}}$ = $\displaystyle -{20 \over 9} \approx -2.22$

This answer doesn't exist. So I presume, that my asumption about the value of tan(x) was incorrect. But maybe you can use my explanations when you plug in the right value for tan(x).

Greetings

EB - May 11th 2006, 04:33 PMtopsquarkQuote:

Originally Posted by**cheesepie**

Thus: $\displaystyle sin \,x = \pm \sqrt{1-0.6^2}=\pm 0.8$

Since tan x is negative, sin x = -0.8

Thus csc x = 1/sin x = 1/-0.8 = -1.25

-Dan