Trig hep, please? Thank you!

posted by .

1. Find the exact value of sin(195(degrees))

2. If cot2(delta)=5/12 with 0(<or =)2(delta)pi, find cos(delta), sin(delta) , tan(delta).

3.find the exact value of sin2(x) if cos(x)= 4/5. (X is in quadrant 1)

4. Find the exact value of tan2(x) if sin(x)=5/13. ((X) in quadrant 2)

5. Solve sin2(x)+sin(x)=0 for 0<or=x<or=2pi.

6. Write 2sin37(degrees)sin26(degrees) as a sum (or difference).

  • Trig hep, please? Thank you! -

    1.
    sin 195°
    = - sin15° , by CAST

    we know cos 30° = 1 - 2 sin^2 15°
    √3/2 = 1 - 2sin^2 15°
    2sin^2 15 = 1 - √3/2 = (2-√3)/2
    sin^2 15° = (2-√3)/4

    sin 15 = √((2-√3)) /2

    so sin 195
    = -sin15
    = -√((2-√3)) /2

    3. given cos x = 4/5 , x in I
    then by Pythagoras, sinx = 3/5

    sin 2x = 2sinx cosx
    = 2(3/5)(4/5) = 24/25

    5.
    sin 2x + sinx = 0 , 0 ≤ x ≤ 2π

    2sinxcosx + sinx = 0
    sinx(2cosx + 1) = 0
    sinx = 0 or cosx = -1/2

    x = π/2
    x = 3π/2

    x = π-π/3 = 2π/3 ---- ( 120°)

    Give the others a try, let me know what you got
    x = π+π/3 = 4π/3 ---- (240°)

  • Trig hep, please? Thank you! -

    thanks! what do the question marks stand for.

    and also CAST?

  • Trig hep, please? Thank you! -

    I will try the others soon.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math

    Compute delta(y) and dy for the given values of x and dx=delta(x) y=x^2 , x=8 , delta(x)=0.5 Delta(y)= ?
  2. Chemistry

    Clapeyron equation: dp/dT = ΔS / ΔV My textbook says, for fusion/melting reactions: dp/dT = ΔH / (T ΔV) this implies that T * ΔS = ΔH. I know T * ΔS = q and at constant pressure, that equals …
  3. Chemistry(Please check answers)

    1) For a reaction delta Go is more negative than delta Ho. What does this mean?
  4. math

    lim delta x to 0 of sin[(pi/6)+delta x]-(1/2) all divided by delta x hope i made that clear. hint given: sin(theta+gamma)=sin theta cos gamma+cos theta sin gamma sorry not sure where to start on this one
  5. Math

    This is gr 12 calculus btw I need helping in filling in the blanks/ -the angle formed at the centre of the circle by two radii is the _______ angle. -cos delta, sin delta, tan delta are known as the ___________trigonometric ration …
  6. Grade 12 Calculus

    I need helping in filling in the blanks/ -the angle formed at the centre of the circle by two radii is the _______ angle. -cos delta, sin delta, tan delta are known as the ___________trigonometric ration -cos (pie/2 - x)=sinx is an …
  7. Chemistry

    Please explain. The enthalpy changes for two different hydrogenation reactions of C2H2 are: C2H2+H2---->C2H4 Delta H 1 C2H2+2H2---->C2H6 Delta H 2 Which expression represents the enthalpy change for the reaction below?
  8. CHEMISTRY

    Please explain. The enthalpy changes for two different hydrogenation reactions of C2H2 are: C2H2+H2---->C2H4 Delta H 1 C2H2+2H2---->C2H6 Delta H 2 Which expression represents the enthalpy change for the reaction below?
  9. math

    Given z=cos*(delta)+j sin*(delta),show that z^n+1/(z^n)=2cos*n*(delta)
  10. Climate Physics

    Find the insolation in Wm^-2 at summer solstice for a low obliquity of 22 degrees?

More Similar Questions