Trigonometry Practice Test 1

© examsiri.com

Question : 30 of 40

Marks: +1, -0

If 2 sin θ = sec θ, what is the value of

\sin^4 θ + \cos^4θ

?

1
$1/2$
$1/4$
$1/8$
None of these

Solution:

Since,

2 \sin θ = \sec θ

⇒ 2 \sin θ =1/{\cosθ}

⇒2\sinθ\cosθ=1⇒\sin2θ=1

......(i)
Now,

\sin^4 θ + \cos^4θ

=(\sin^2θ+\cos^2θ)^2-1/2\sin^2 2θ

=1-1/2\sin^2 2θ

=1-1/2=1/2

[From (i)]

© examsiri.com

Go to Question:

Prev Question

Next Question