Sunday

April 20, 2014

April 20, 2014

Posted by **Anonymous** on Saturday, September 3, 2011 at 4:46pm.

Sec^-1(-2)

Sec^-1(-sqrt2)

Tan^-1(-sqrt3)

Tan^-1(sqrt3)

- trig -
**Reiny**, Saturday, September 3, 2011 at 8:25pmI will do the 2nd one:

sec^-1 (-√2) = Ø , such that sec Ø = -√2

or

cos Ø = -1/√2

I know that cos 45° = 1/√2

but the cosine is negative in II and III

so Ø = 180-45° = 135°

or Ø = 180+45 = 225°

They probably expect the answer of 135° or 3π/4 radians

- trig -
**Anonymous**, Sunday, September 4, 2011 at 1:56pmHow did you come up with 135 being the answer? I understand what you did but you said it could also be 225, so what makes you pick 135?

- trig -
**Charles**, Sunday, September 4, 2011 at 2:17pmAlso doesnt the cos45 = sqrt2/2 not 1/sqrt 2?

- trig -
**Steve**, Wednesday, September 21, 2011 at 1:14pmyes, because sqrt2/2 = 1/sqrt2

**Related Questions**

trig - Write the expression and evaluate. There is only one answer whIch should ...

trig - Write the expression and evaluate. There should only be one answer which ...

algebra - ***show work evaluate the expression: 7^-6 (-6)^-9 simplify the ...

Algebra - Use symbols to write the expression and then evaluate it Thirty six ...

Math - Write an algebraic expression for each word phrase on the board. Evaluate...

math 115 - 1. divide 36/-4= 9 is this correct? 2. evaluate the expression |-5 +3...

trig - How do you evaluate the expression cos3pi

MATH URGENT - Write the calculator key sequence you would use to evaluate each ...

Evaluate Expression - 6.Evaluate the following. 4*4-14/2+6 my answer =15 7....

math 115 - 1.evalute the expression -8 + 15 = 7 is this answer correct? 2....