Monday

September 22, 2014

September 22, 2014

Posted by **Abby** on Wednesday, March 23, 2011 at 10:22pm.

A) 0, 1.571 B) -1.571, 0, 1.571 C) -1.369, 0, 1.369 D) 0, 1.369

- Pre Calc -
**Jai**, Wednesday, March 23, 2011 at 10:37pmrecall that tan(x) can be rewritten as

tan (x) = sin (x) / cos (x)

substituting:

sin(x) / cos(x) = 5 sin(x)

the sin(x) will be cancelled:

1/cos(x) = 5

cos(x) = 1/5

solving this,

x = +/- 1.369

since it must be on interval -π < x < π

x = - 1.369

- Pre Calc -
**Reiny**, Wednesday, March 23, 2011 at 10:39pmare we solving ????

tanx = 5sinx

sinx/cosx= 5sinx

sinx = 5sinxcosx

sinx - 5sinxcos)=0

sinx(1 - 5cosx) = 0

sinx = 0 or cosx = 1/5

if sinx = 0, x = 0, π or 2π

if cosx = 1/5, x = 1.369 or -1.369 if -π < x < π

so for the given domain

x = -1.369 , 0, 1.369 , which would be choice C)

- Pre Calc -
**Abby**, Wednesday, March 23, 2011 at 10:52pmThanks so much guys!!!!

- Pre Calc -
**Reiny**, Wednesday, March 23, 2011 at 10:58pmDid you notice that Jai missed one of the answers of

x = 0.

You should not cancel sinx , but rather use it as one of the factors.

by canceling sinx , he "lost" the answer to sinx = 0

- Pre Calc -
**Jai**, Wednesday, March 23, 2011 at 11:18pmoh yeah,, sorry about that. 0 is also a solution~

thanks for correcting me, sir~ :)

**Answer this Question**

**Related Questions**

Math - Evaluate *Note - We have to find the exact value of these. That I know to...

Math, please help - Which of the following are trigonometric identities? (Can be...

Precalculus - Use one of the identities cos(t + 2πk) = cos t or sin(t + 2&#...

Math integrals - What is the indefinite integral of ∫ [sin (π/x)]/ x^...

Pre Calc - evaluate the trigonometric function of the given quadrantal angle. ...

Pre-Calc : Verify the Identity - Verify the Identity: sin(x+π)/cos(x+3π...

Calculus - How do I find the critical values? y= 4/x + tan(πx/8) What I ...

Trig Help! - Question: Trying to find cos π/12, if cos π/6 = square ...

Trigonometry - IM STUCK ON THESE :( 1. What is the equation for shifting the ...

Trigonometry - IM STUCK ON THESE :( 1. What is the equation for shifting the ...