High School Solving Simultaneous equations with cos() and sin()

[Micheal_Leo]

Hello

I have two equations given below and answer is also given solve by simultaneously

i am not sure how this happen

please guide thank you

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[anuttarasammyak]

Use the identity
\sin^2\theta_s+\cos^2\theta_s=1

 

[Micheal_Leo]

Use the identity
\sin^2\theta_s+\cos^2\theta_s=1

thank you for reply , first have to take square on both sides of equation 1 and 2 than use identity ?

 

[anuttarasammyak]

Get
V sin\theta_s, V cos\theta_s
exlpcit and use the identity.

 

[Micheal_Leo]

Get
V sin\theta_s, V cos\theta_s
exlpcit and use the identity.

thank you very much perfectly got it