Question

Pls frnds pls answer this is puzzling my mind ,i.e.,if sin theta=1.5,then cos theta=?????
?

Answer 1

Find sinθsin⁡θ if tanθ+secθ=1.5tan⁡θ+sec⁡θ=1.5

tanθ+secθ=1.5tan⁡θ+sec⁡θ=1.5

2tanθ+2secθ=32tan⁡θ+2sec⁡θ=3

2secθ=3−2tanθ2sec⁡θ=3−2tan⁡θ

4sec2θ=(3−2tanθ)24sec2⁡θ=(3−2tan⁡θ)2

4+4tan2θ=9−12tanθ+4tan2θ4+4tan2⁡θ=9−12tan⁡θ+4tan2⁡θ

So I get

tanθ=512tan⁡θ=512

Thus

sinθ=513sin⁡θ=513

But If I do like this ,

sinθcosθ+1cosθ=32sin⁡θcos⁡θ+1cos⁡θ=32

2sinθ+2=3cosθ2sin⁡θ+2=3cos⁡θ

(2sinθ+2)2=9cos2θ(2sin⁡θ+2)2=9cos2⁡θ

4sin2θ+8sinθ+4=9−9sin2θ4sin2⁡θ+8sin⁡θ+4=9−9sin2⁡θ

13sin2θ+8sinθ−5=013sin2⁡θ+8sin⁡θ−5=0

Therefore I get two answers

sinθ=513,sinθ=−1

Answer 2

Answer:

Step-by-step explanation:

Sin ∅ = 1.5

= 15/10

Sin²∅ = 225/100 ( squaring both sides)

We know that,

Sin²∅ + cos²∅ = 1

225/100 + cos²∅ = 1

Cos²∅ = 1 - 225/100

Cos²∅ = 100 -225 /100

cos²∅ = - 125 /100

cos∅ = √125 /100 (taking sq. rt. on both sides)

Cos ∅ = 5√5 /100

Cos∅ = √5 /20

Therefore the value of cos∅ Is √5/20