# Can someone help me solve this problem: cos^2x + 5cosx - 2= 0 I am having trouble finding x

47,879 results
1. ## Math

Solve 6sin^2 x-5cosx-2=0 in the interval 0≤x≤2π

2. ## Trigonometry

How do I solve these? 1) 2sinxcosx-cosx=0 2) cos^2(x)-0.5cosx=0 3) 6sin^2(x)-5sinx+1=0 4) tan^2(x)+tanx-12=0

3. ## Trigonometry

4. Find the exact value for sin(x+y) if sinx=-4/5 and cos y = 15/17. Angles x and y are in the fourth quadrant. 5. Find the exact value for cos 165degrees using the half-angle identity. 1. Solve: 2 cos^2x - 3 cosx + 1 = 0 for 0 less than or equal to x

4. ## Calculus AP

Evaluate the integral interval from [0 to pi] t sin(3t)dt Use integration by parts u=t and dv=sin(3t)dt. then du=dt and v=-cos(3t)/3 here is my problem but Im having problem to solve with pi. ∫t sin(3t)dt = -tcos(3t)/3 - ∫[-cos(3t)/3]dt =-tcos(3t)/3 +

5. ## PreCal

Solve the following equation for all solutions: cos(5x)cos(3x)-sin(5x)sin(3x)=√3/2. I know the formula to use would be cos(A+B), but I'm just not confident in my ability to solve it correctly.

6. ## Pre Cal

Solve 4sin^2 x + 4sqrt(2) cos x-6 = 0 for all real values of x. My answer: (pi/4)+2(pi)k, (7pi/4) + 2(pi)k Solve 2cos^2 x-5cosx+2=0 for principal values of x. My answer: 60 and 300 degrees

7. ## trig

Solve for all real values of x 3cos2x - 5cosx = 1

8. ## math

Solve 3sin2x - 1 = 0 Interval: [0, 2 pi] Solve 6cos^2x + 5cosx - 6 = 0

9. ## trig

2(sinx)^2-5cosx-4=0 Solve for all solutions between [0,2pi]

10. ## Math/Physics

My question is this: The potential at the surface of a sphere (radius R) is given by V_0 = k cos 3theta where k is constant. Find the potential inside and outside the sphere as well as the surface charge density (lower case sigma(theta)) on the sphere.

11. ## Math (Trigonometry [Polar Form])

Let z be a complex number such that z = 2(cos 8∘ + i cos 82∘).Then z^5 can be expressed as r(sin α∘+ i cos α∘), where r is a real number and 0 ≤ α ≤ 90. What is the value of r+α? Hint to solve: Example Question: Let z be a complex number

12. ## Maths

Solve the initial value problem (dx/dt)+2x=cos(2t) with x(0)=5

13. ## Trigonometric

Consider the following simultaneous equations: 3 cos^2 𝛼 + 2 cos^2 𝛽 =4 3 sin^2 𝛼 − 2sin^2 𝛽=0 *Find the values of cos 2𝛼 and cos 2𝛽. *Hence solve for 𝛼𝛼 and 𝛽𝛽. Where 0°≤𝛼𝛼≤360° and 0°≤𝛽𝛽≤360°.

14. ## math

Ajax is 8 km due west of Oshawa. Uxbridge is 16 km NW of Oshawa. How far is it from Ajax to Uxbridge? Explain whether you have enough information to solve this problem. my answer was 13.856 km but not confident how I found the angle oshawa to begin with. I

15. ## Trigonometry

Solve the equation for solutions in the interval 0

16. ## trig

Find arcsin [cos (Pi/2)] The answer is 0. How do you solve this problem? Thanks.

17. ## math

solve 2cos^2x-5cosx+2=0 for principal values of x I don't understand this question...what are principal values?

18. ## Trig

Compute inverse functions to four significant digits. cos^2x=3-5cosx rewrite it as.. cos^2x + 5cosx -3=0 now you have a quadratic, solve for cos x using the equation cosx=(-5 -+ sqrt (25 +12)/2

19. ## calculus

Differentiate. y= (cos x)^x u= cos x du= -sin x dx ln y = ln(cos x)^x ln y = x ln(cos x) (dy/dx)/(y)= ln(cos x) (dy/dx)= y ln(cos x) = (cos x)^x * (ln cos x) (dx/du)= x(cos x)^(x-1) * (-sin x) = - x sin(x)cos^(x-1)(x) (dy/dx)-(dx/du)=

20. ## precalculus

I don't understand this problem: (Tanө + cos ө)/ (sec ө + cot ө) so I start off like this: ={(sinө / cos ө)+cosө}{cos ө + (sinө/cosө)} =[(sin ө +cos^2ө) (cos^2ө +sin ө)]/ cos ө but what comes next?

21. ## Calculus

Please look at my work below: Solve the initial-value problem. y'' + 4y' + 6y = 0 , y(0) = 2 , y'(0) = 4 r^2+4r+6=0, r=(16 +/- Sqrt(4^2-4(1)(6)))/2(1) r=(16 +/- Sqrt(-8)) r=8 +/- Sqrt(2)*i, alpha=8, Beta=Sqrt(2) y(0)=2, e^(8*0)*(c1*cos(0)+c2*sin(0))=c2=2

22. ## trig

it says solve for all real solutions, compute inverse functions to 4 sigfigs. cos^2x=3-5cosx Devon, what grade level are these questions from? I am having the same problems as with your 9:14 post. Please see my partial solution in the post to bobpursely at

23. ## trig

2sin(x)cos(x)+cos(x)=0 I'm looking for exact value solutions in [0, 3π] So I need to find general solutions to solve the equation. But do I eliminate cos(x), like this... 2sin(x)cos(x)+cos(x)=0 2sin(x)cos(x)= -cos(x) 2sin(x) = -1 sin(x) = -1/2 at 4pi/3

24. ## another precal

i have two questions for you to check please! 6cos^2x+5cosx-4=0 where 0degrees < or equal to 0 which is < or equal to 360. I got that this factors to (3x+4)(2x-1) so the answer is x= -4/3 and x= 1/2 ?? right? and the second question: determine sin2theta,

25. ## trig question

Compute inverse functions to four significant digits. cos^2x=3-5cosx cos^2x + 5cosx -3=0 now you have a quadratic, solve for cos x using the equation cosx=(-5 -+ sqrt (25 +12)/2 the back of the book says .9987+2kpi and -.09987+2kpi when i do it i don't get

Can someone help me solve this problem: cos^2x + 5cosx - 2= 0 I am having some trouble finding x

27. ## Trig/Precalc

So I have two questions that have been puzzling me for quite some time and would really appreciate any help with either of them! (a) There are four positive intergers a, b, c, and d such that 4cos(x)cos(2x)cos(4x)=cos(ax)+cos(bx)+cos(cx)+cos(dx) for all

28. ## Calculus AP

hi again im really need help TextBook: James Stewart:Essential Calculus, page 311. Here the problem #27: First make a substitution and then use integration by parts to evaluate the integral. Integral from sqrt(pi/2) TO sqrt(pi)of θ^3 cos(θ^2)dθ. i did

29. ## pre-calc

Solve: cos(2x-180) - sin(x-90)=0 my work: cos2xcos180 + sin2xsin180= sinxcos90 - sin90cosx -cos2x - sin2x= cosx -cos^2x + sin^2x -2sinxcosx=cosx I'm stuck here. I tried subtracting cosx from both sides and making sin^2x into 1- cos^2x, but I still can't

30. ## Math/Calculus

Please check my work and correct any errors/point out any errors. Thanks. Solve the initial-value problem using the method of undetermined coefficients. y''-4y=e^xcos(x), y(0)=1, y'(0)=2 r^2-4=0, r1=2, r2=-2 yc(x)=c1*e^2x+c2*e^-2x

31. ## trig

Please help me solve this problem. I have a test tomorrow and I do not understand at all. Determine all solutions of the equations in radians. Find cos x/2, given that cos x = 1/4 and x terminates in 0 < x < π/2.

32. ## Pre-Cal (Trig) Help?

The following relationship is known to be true for two angles A and B: cos(A)cos(B)-sin(A)sin(B)=0.957269 Express A in terms of the angle B. Work in degrees and report numeric values accurate to 2 decimal places. So I'm pretty lost on how to even begin

33. ## calculus

find max, min and saddle points of the give function f(x,y)=sin(x)+sin(y)+sin(x+y) 0

34. ## Math - Solving for Trig Equations

Solve the following equation for 0 less than and/or equal to "x" less than and/or equal to 360 -- cos^2x - 1 = sin^2x -- Attempt: cos^2x - 1 - sin^2x = 0 cos^2x - 1 - (1 - cos^2x) = 0 cos^2x - 1 - 1 + cos^2x = 0 2cos^2x - 2 = 0 (2cos^2x/2)= (-2/2) cos^2x =

35. ## Maths

Solve the following equations for -180《 x《 180 A) 4+4cosx=sin^2x B) 2sin=5cosx Thankyou

36. ## Trigonometric

Consider the following simultaneous equations: 3 cos^2 𝛼 + 2 cos^2 𝛽 =4 3 sin^2 𝛼 − 2sin^2 𝛽=0 *Find the values of cos 2𝛼 and cos 2𝛽. *Hence solve for 𝛼 and 𝛽. Where 0°≤𝛼≤360° and 0°≤𝛽≤360°.

37. ## pre-calc help !!!!!!!

if someone could show me how to solve this problem 1) cos(345°)

38. ## TRIG!

Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6 x=1 - (3/4)sin^2 2x work on one side only! Responses Trig please help! - Reiny, Monday, February 23, 2009 at 4:27pm LS looks like the sum of cubes sin^6 x + cos^6 x = (sin^2x)^3 +

39. ## pre-cal

Simplify the given expression........? (2sin2x)(cos6x) sin 2x and cos 6x can be expressed as a series of terms that involve sin x or cos x only, but the end result is not a simplification. sin 2x = 2 sinx cosx cos 6x = 32 cos^6 x -48 cos^4 x + 18 cos^2 x -

40. ## calculus

can you pleaaaaase help me find the area between y=cos(4x) and y=1-cos(4x) 0

41. ## differential Equations

solve the initial value problem and find the interval of existence... cos(y) dy/dt = -t sin(y)/ (1+t^2) , y(1)=pi/2

42. ## math

Find the exact value of cos 300 degrees. thanks guys cos 300 = 1/2 = 0.500 how do you know? I am supposed to show my work. You ought to know the rule on 30-60-90 triangles. If the hyp is 2, the shorter side is 1, and the longer side is sqrt3. what does

43. ## Child development

Using these steps, consider a cognitive “problem” a young child might encounter that he/she needs help with (such as putting together a puzzle, sequencing – putting items in order, sorting by color or size, adding, subtracting, tying shoes, learning

44. ## Calculus - Second Order Differential Equations

Posted by COFFEE on Monday, July 9, 2007 at 9:10pm. download mp3 free instrumental remix Solve the initial-value problem. y'' + 4y' + 6y = 0 , y(0) = 2 , y'(0) = 4 r^2+4r+6=0, r=(16 +/- Sqrt(4^2-4(1)(6)))/2(1) r=(16 +/- Sqrt(-8)) r=8 +/- Sqrt(2)*i,

45. ## MATH

in a contest, Bello. Adamu, and Lawi are asked to solve a mathematical problem. the probability that they solve the problem correctly are 1/5, 2/3, and 2/5. find the probability that:(1)None of them solve the problem correctly(2)At least one of them solve

46. ## Pre Calculus

Can someone help me solve this problem: cos^2x + 5cosx - 2= 0 I am having trouble finding x

47. ## Advanced Math

Solve 4sin^2 x + 4sqrt(2) cos x-6 = 0 for all real values of x. My answer: (pi/4)+2(pi)k, (7pi/4) + 2(pi)k Solve 2cos^2 x-5cosx+2=0 for principal values of x. My answer: 60 and 300 degrees.

48. ## Pre Cal.

So I posted these...but no one answered them. Are they right? Solve 4sin^2 x + 4sqrt(2) cos x-6 = 0 for all real values of x. My answer: (pi/4)+2(pi)k, (7pi/4) + 2(pi)k Solve 2cos^2 x-5cosx+2=0 for principal values of x. My answer: 60 and 300 degrees

49. ## calculus

pleaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaasw help can you pleaaaaase help me find the area between y=cos(4x) and y=1-cos(4x) 0

50. ## Precal

I do not understand how to do this problem ((sin^3 A + cos^3 A)/(sin A + cos A) ) = 1 - sin A cos A note that all the trig terms are closed right after there A's example sin A cos A = sin (A) cos (A) I wrote it out like this 0 = - sin^6 A - cos^6 A +

51. ## Precalculus

Solve Cos^2(x)+cos(x)=cos(2x). Give exact answers within the interval [0,2π) Ive got the equation down to -cos^2(x)+cos(x)+1=0 or and it can be simplified too sin^2(x)+cos(x)=0 If you could tell me where to go from either of these two, it would be great

52. ## Math (trigonometry)

How do you solve this trig identity problem without factoring? I just used @ to represent theta: sin^4@ + 2sin^2@cos^2@ + cos^4@ = 1

53. ## Physics (Calc Based)

I understand how to solve this problem ,however cannot figure out why the .5 degrees is being converted to radians: PROBLEM: How would one determine the percent uncertainty in theta and in sin of theta for the following: 1) theta = 15.0 degrees +/- 0.5

54. ## Maths

Please solve this trigonometric identity proof problem. I have completed 20; this is the hardest one. Many thanks (sin^3(x)-cos^3(x))/sin(x)-cos(x)=1+sin(x)cos(x)

55. ## Calc.

Differentiate. y= (cos x)^x u= cos x du= -sin x dx ln y = ln(cos x)^x ln y = x ln(cos x) (dy/dx)/(y)= ln(cos x) (dy/dx)= y ln(cos x) = (cos x)^x * (ln cos x) (dx/du)= x(cos x)^(x-1) * (-sin x) = - x sin(x)cos^(x-1)(x) (dy/dx)-(dx/du)=

56. ## Trigonometry

Write equivalent equations in the form of inverse functions for a.)x=y+cos è b.)cosy=x^2 (can you show how you would solve) a.) x= y+ cos è cos è = x-y theta = cos^-1(x-y) b.) cosy=x^2 cos(y) = x^2 y = Cos^-1(x^2)

57. ## Math - Trigonometry

Let f(x) be a polynomial such that f(cos theta) = cos(4 theta) for all \theta. Find f(x). (This is essentially the same as finding cos(4 theta) in terms of cos theta; we structure the problem this way so that you can answer as a polynomial. Be sure to

ok, i tried to do what you told me but i cant solve it for c because they cancel each others out! the integral for the first one i got is [sin(c)cos(x)-cos(c)sin(x)+sin(x)+c] and the integral for the 2nd one i got is [-sin(c)cos(x)+cos(c)sin(x)-sin(x)+c] I

59. ## Math - Solving Trig Equations

Solve each equation for o is less than and/or equal to theta is less than and/or equal to 360 -- sin^2x = 1 = cos^2x -- Work: cos^2x - cos^2x = 0 0 = 0 -- Textbook Answers: 90 and 270 -- Btw, how would you isolate for cos^2x = 0? Would it be... x = cos^-1

60. ## algebra

Can someone please help me do this problem? That would be great! Simplify the expression: sin theta + cos theta * cot theta I'll use A for theta. Cot A = sin A / cos A Therefore: sin A + (cos A * sin A / cos A) = sin A + sin A = 2 sin A I hope this will

61. ## Precalculus 2

Similiarly to a question I asked previously I took the same approach. the problem is: what value(s) of theta solve the following equation? cos(theta)sin(theta) - 2 cos(theta) = 0? I let Cos theta = X and sin theta = X unfortunately I end up with something

62. ## Math, Pre-Calc

the original problem was: Solve: sin(3x)-sin(x)=cos(2x) so far i've gooten to: sin(x)(2sin(x)cos(x)-1)=cos^2(x)-sin^2(x) Where would I go from here?

63. ## Algebra

I cannot solve the problem please help me. I'm suppose to set the equations up to solve for t. x = y + rt + at^2/2 Even when I plug in the values I don't get the answer. x = 16.4 y= 0 r= 0*cos(45)a=0 t is suppose to equal 2.32 if I set the problem up

64. ## Precalculs

I have no idea how to do these type of problems. -------Problem-------- Solve each equation on the interval 0 less than or equal to theta less than 2 pi 42. SQRT(3) sin theta + cos theta = 1 ---------------------- There is an example prior to the

65. ## Math

Solve this equation algebraically: (1-sin x)/cos x = cos x/(1+sin x) --- I know the answer is an identity, and when graphed, it looks like cot x. I just don't know how to get there. I tried multiplying each side by its conjugate, but I still feel stuck.

66. ## Math

Solve simultaneously for the two equations for x and y 5x(cos 45) + 15y(cos 30) = 2,000 5x(sin45) - 15y(sin 30) = 0 I tried adding these two eqn. to elimate y and solve for x by adding [5 x cos 45] and [5 x sin 45] but the value for x is too high. Would I

67. ## Math

the original problem was: Solve: sin(3x)-sin(x)=cos(2x) so far i've gotten to: sin(x)(2sin(x)cos(x)-1)=cos^2(x)-sin^2(x) Where would I go from here?

68. ## sydney

how would you solve this problem cos(theta)/2=1/6

69. ## Math

How would you solve this problem? cos x/1+sinx

70. ## Calculus

how do you solve this trig identity? i don't get it at all! cos(a+b)cos(a-b)=cos^2a-cos^2b-1

71. ## math

How to solve for delta using trig functions? i.e. cosine sine tangent secant Thank you I'm not sure what delta you're referring to. Could you please elaborate some for us. What is it you're trying to do with the trig funtions? the problem is.. limit sec

72. ## Maths

Solve the initial value problem (dy/dt)+2y=15 sin(t)+15 cos(t) with y(0)=3

73. ## Pre Calculus

Solve 2cos^2(2x)=1 I divided both sides by 2 and got this cos^2(2x)=1/2 But then I didn't know what to do after that... The part that has me stumped is that it's a cos^2(2x) not just a cos^2x. Any advice on what I should try next?

74. ## trigonometric functions

Solve and state the general solution for all values of x in exact form. Show all steps algebraically. sin^2 𝑥 − √2 cos 𝑥 = cos^2 𝑥 + √2 cos 𝑥 + 2

75. ## Calculus

My book says to do the following problem via computer and via hand: Calculate the definite Integral of e^-x * cos x dx over (0, +infinity) My TI-89 calculator gets 1 (it gets the same thing when I replace infinity with 999). when I do this by hand, I get:

76. ## Calculus AP

Use the table of integrals to find int cos^4 3x dx I found the table: ∫cos^n u du = (1/n)cos^(n-1)u sinu + (n-1/n)∫sin^(n-2)u du = 1/4 cos^(4-1)u sinu + (4-1/4)∫sin^(4-2) u du so what i did the problem: let u=3x then du=3dx =1/4*1/3 cos^3u sinu +

77. ## relative velocity

A radar antenna is tracking a satellite orbiting the earth. At a certain time, the radar screen shows the satellite to be 159km away. The radar antenna is pointing upward at an angle of 59.3 from the ground.Fine the x and y components(in km) of the

78. ## calculus

solve for the second derivative and set to zero f"(x) = ((x^2-4)*sin(2x)- [(2x)(1+cos^2(x))]/ ((1+cos^2(x))^2) i don't know how to set it to zero and solve i get this: (x^2-4)(sin(2x))= (2x)(1+cos^2(x)) thanks for help i did not get a clear response

79. ## Math

To solve this problem, use the Pythagorean Theorem to find the third side. Cos=5/7

80. ## math

What is the value of y if y=cos(Arc sin 1/2)? How can I solve this problem? Please help and explain! THANKS A LOT!

81. ## Math (Answer ASAP)

To solve this problem, use the Pythagorean Theorem to find the third side. Cos=5/7

82. ## Pre-Calculus

I need help-I do not understand. The question is this: Write 2x+y=5 in polar form. By following the example in the book I get: 5sqrt5/5=1/sqrt5*sqrt5/2. I do not know how to proceed but the answers I have to choose from are: a) -sqrt5=r cos(theta-27

83. ## Calc

h(x) = {k cos x 0 ≤ x ≤ 9π {13 − x 9π < x So far I've set it up to be 13 - 5π = k cos 5π but I'm completely stuck now. I tried to solve it and got (cos^-1 (13-5π)) / 5π but i know I messed up somewhere. Can anyone help?

84. ## Calculus

g(x)={1+cos(pi/2-x/1) 0 for-2

85. ## math/Calc

g(x)={1+cos(pi/2-x/1) 0 for-2

86. ## Trigonometry desperate help, clueless girl here

2. solve cos 2x-3sin x cos 2x=0 for the principal values to two decimal places. 3. solve tan^2 + tan x-1= 0 for the principal values to two decimal places. 4. Prove that tan^2(x) -1 + cos^2(x) = tan^2(x) sin^2 (x). 5.Prove that tan(x) sin(x) + cos(x)=

87. ## Math

1. Solve cos x(cos x - 1) = 0. Ans: pi/2 + n pi, and 2 n pi 2. 2 cos x - 1 = 0 Ans: x = pi/3 + 2 n pi, and x = 5pi/3 + 2 n pi 3. Solve 4 sin^2 x - 3 = 0 Ans: x = pi/3 + n pi, and 2pi/3 + n pi 4. What is one solution to (sqrt2) sinx + 1 = 0? Ans: x = pi/6

88. ## Trigonometry

Okay, I have been given a trigonometric equation to solve (sin^2(theta) + cos(theta) = 2). So far, I have been able to use the Pythagorean identity to get (-cos^2(theta) + cos(theta) - 1 = 0), which I then multiplied by -1 on both sides to get:

89. ## math

determine vectors u and v are parallel ,orthogonal or neither u=(2,5) v=(10/3,4/3) please use ab=|a|•|b|•cos theta to solve this problem!!! thx

90. ## maths

Find the roots of z^6 + 1 and hence resolve z^6 + 1into read quadratic factors; deduce that cos3x = 4[cos(x) -cos(pi/6)][(cos(x) -cos(pi/2)][(cos(x) -cos(5pi/6)]

91. ## maths

Find the roots of z^6 + 1 and hence resolve z^6 + 1into read quadratic factors; deduce that cos3x = 4[cos(x) -cos(pi/6)][(cos(x) -cos(pi/2)][(cos(x) -cos(5pi/6)]

92. ## math

I need to use calculus to solve this word problem: Find all maximum and minimum values for f(x)= sin(x)+ cos(x) on [0, 2(3.14)] How do I do it?

93. ## math

Can someone help me solve this problem: cos^2x + 5cosx - 2= 0 I don't know how to find x

94. ## Math

How would you solve this problem? Please include steps for me! Solve for θ in the interval 0 ≤ θ ≤ 2π: cos(θ )sin(θ ) − 1/ 2cos(θ ) = 0

95. ## Trig identies, Calculus

Use the identities cos^2 x + sin^2 x =1 and cos2x=cos^2 x -sin^2 x to show that cos^4 x -sin^4 x = cos2x Im not sure how, I can solve my problem with half angle identities but im not sure where to start with this.

96. ## math

I am solving a problem and have -cos(a)=-1/2. How do I solve for a?

97. ## Trigonometry

Verify/Solve the identities. 1.) SIN^1/2 X COS X-SIN^5/2 X COS X 2.) Long problem, but it's fun to solve! SEC^6 X(SEC X TAN X)-SEC^4 X(SEC X TAN X)

98. ## cosines

I don't know how to reverse cosine decimals into angles. Can you please explain and help me solve these . cos A= 0.28571428571 A= cos B= 0.66666666667 B= cos C= 0.5238089523

99. ## Trigonometry

I need help with the inverse of si, cos, & tan. So far on one problem I've gotten sinX = 29/14 where do I go from here? I know you have to use cos^-1, but how? Can anyone work this one problem out for me to see how to do it? THANKS!

100. ## math

Determine exact value of cos(cos^-1(19 pi)). is this the cos (a+b)= cos a cos b- sina sin b? or is it something different. When plugging it in the calculator, do we enter it with cos and then the (cos^-1(19 pi)).