1. If cscθ=5/3 then secθ=
a. 25/16
b. 5/4
c. 16/25
d. 4/5

2. Simplify the expression
(cos x) (sec x) - (sin2 x)
a. cos x
b. cos2 x
c. sec2 x

3. If θ is in Quadrant IV and sinθ=-5/4 then secθ=
a. -13/12
b. -12/3
c. 12/13
d. 13/12

Respuesta :

Answer:

(1)

b. [tex]sec(\theta)=\frac{5}{4}[/tex]

(2)

b. [tex]cos^2(x)[/tex]

(3)

[tex]sec(\theta)=\frac{13}{12}[/tex]


Step-by-step explanation:

(1)

we are given

[tex]csc(\theta)=\frac{5}{3}[/tex]

we can use triangle method

we know that

csc=hyp/ opposite

so, hyp=5

opposite =3

now, we can find adjacent

we can use Pythagoras theorem

[tex]hyp^2=opp^2+adj^2[/tex]

[tex]5^2=3^2+adj^2[/tex]

[tex]adj=4[/tex]

now, we can find sec

[tex]sec(\theta)=\frac{5}{4}[/tex]


(2)

we are given

[tex](cosx)(secx)-sin^2(x)[/tex]

we can simplify it

[tex](cosx)\times (\frac{1}{cosx})-sin^2(x)[/tex]

[tex]1-sin^2(x)[/tex]

now, we can replace 1 as sin^2x +cos^2x

we get

[tex]sin^2(x)+cos^2(x)-sin^2(x)[/tex]

[tex]=cos^2(x)[/tex]

(3)

we are given

θ is in Quadrant IV

[tex]sin(\theta)=\frac{-5}{13}[/tex]

we know that

sin =opp/hyp

so, opp=5

hyp=13

now, we can use Pythagoras theorem

[tex]hyp^2=opp^2+adj^2[/tex]

now, we can plug values

[tex]13^2=5^2+adj^2[/tex]

[tex]adj=12[/tex]

sec=hyp/adj

so, we get

[tex]sec(\theta)=\frac{13}{12}[/tex]