Question

3. Let sin 21 = 0.358. What is the value of x for cos x=0.358?

Answer 1

Answer:

$\cos(69)$

Step-by-step explanation:

We will use the co-function identity for sine, where:

$\sin(x)=\cos(90-x)$

Since sin(21)=0.358=cos(x). This means that:

$21=90-x$

Solve for x. Add x to both sides:

$x+21=90$

Subtract 21 from both sides:

$x=69\textdegree$

Hence:

$\sin(21)=\cos(69)\approx0.358$