Precalculus check answers help!

posted by .

1. Which expression is equivalent to cos 2theta for all values of theta ?

cos^2 theta – sin^2 theta ~
cos^2 theta – 1
1 – 2 sin^2 theta
2 sin theta cos theta

2. Use a half–angle identity to find the exact value of sin 105°.

-1/2(sqrt)(2 + Sqrt3)
1/2(sqrt)(2 + Sqrt3) ~
1/2(sqrt)(2 + Sqrt2)
11/2(sqrt)(1 + Sqrt3)

3.) Solve cos x tan x - sin^2x = 0 for all real values of x.

piK, pi/2 + 2piK
pi/2 + piK, 2pik
pi/2 + 2piK, 3pi/2 + 2piK
piK, pi/4 +2piK ~


4.) Solve 2 sin2x – sin x = 0 for principal values of x.
60° and 120°
0° and 150° ~
0° and 30°
60°

5.) Solve csc x + 2 = 0 for 0 < x < 2pi.

pi/6 and 5pi/6
pi/6 and 7pi/6
4pi/3 and 5pi/3
7pi/6 and 11pi/6 ~

6.) Solve 2 cos x – 1 = 0 for 0 <x< 2.

pi/6 and 5pi/6
pi/3 and 5pi/3 ~
pi/3 and 2pi/3
7pi/6 and 11pi/6

7.) Write the equation 3x + 4y – 7 = 0 in normal form.

3/5x + 4/5y + 7/5 = 0
-3/5x - 4/5y - 7/5 = 0
-3/5x - 4/5y + 7/5 = 0 ~
3/5x + 4/5y - 7/5 = 0

8.)Write the standard form of the equation of a line for which the length of the normal is 4 and the normal makes an angle of 45° with the positive x–axis.

sqrt2x + sqrt2y +8 = 0
2x + 2y – 8 = 0
sqrt2x + sqrt2y -8 = 0 ~
2x + 2y + 8 = 0

9.) Write the standard form of the equation of a line for which the length of the normal is 3 and the normal makes an angle of 135° with the positive x–axis.
sqrt2^x – sqrt2y + 6 = 0 ~
sqrt2^x + sqrt2y - 6 = 0
sqrt2^x – sqrt2y - 6 = 0
sqrt2^x + sqrt2y + 6 = 0

10.) Find the distance between P (–2, 1) and the line with equation x – 2y + 4 = 0.

4sqrt5/5
0 ~
-4sqrt5/5
5/4

the ones with~ are my answers

  • Precalculus check answers help! -

    #3 should be piK, pi/2 + 2piK since sin=0 or 1

    #4. should be 0° and 30° since they asked for principal values

    1,2,5,6 look good

    7-10 I'll have to check later, or another expert can come by.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Trig

    Which expression equivalent to: cos(theta + pi/2). A)cos theta B)-cos theta C)sin theta D)-sin theta my book doesnt give examples of this but my crack at it would be C b/c distributive property?
  2. Algebra II

    Which of the following expressions are not equal to 1?
  3. Calculus

    I wanted to confirm that I solved these problems correctly (we had to convert the polar curves to Cartesian equations). 1.rcos(theta)=1 x=1 2.r=2*sin(theta)+2*cos(theta) r^2=2rsin(theta)+2rcos(theta) x^2+y^2=2y+2x (a little unsure …
  4. trigonometry

    can you correct the rest for me please? Express each as a function of theta: a. sin (270deg + theta)= cos theta b. cos (pi + theta)= -cos theta c. tan (810 + theta)= ?
  5. trigonometry

    can you correct the rest for me please? Express each as a function of theta: a. sin (270deg + theta)= cos theta b. cos (pi + theta)= -cos theta c. tan (810 + theta)= ?
  6. Algebra II

    Multiple Choice Which expression is NOT equivalent to 1?
  7. Precalculus check answers help!

    1.) Find an expression equivalent to sec theta sin theta cot theta csc theta. tan theta csc theta sec theta ~ sin theta 2.) Find an expression equivalent to cos theta/sin theta . tan theta cot theta ~ sec theta csc theta 3.) Simplify …
  8. Precalculus check answers help!

    1.) Find an expression equivalent to sec theta sin theta cot theta csc theta. tan theta csc theta sec theta ~ sin theta 2.) Find an expression equivalent to cos theta/sin theta . tan theta cot theta ~ sec theta csc theta 3.) Simplify …
  9. Trigonometry

    Prove the following identities: 1. (tan theta - sin theta)^2 + (1-cos theta)^2 = (1-sec theta) ^2 2. (1-2cos^2 theta) / sin theta cos theta = tan theta - cot theta 3. (sin theta + cos theta ) ^2 + (sin theta - cos theta ) ^2 = 2 Thank …
  10. Trigonometry

    Prove the following identities: 1. (tan theta - sin theta)^2 + (1-cos theta)^2 = (1-sec theta) ^2 2. (1-2cos^2 theta) / sin theta cos theta = tan theta - cot theta 3. (sin theta + cos theta ) ^2 + (sin theta - cos theta ) ^2 = 2 Thank …

More Similar Questions