Everything Maths Grade 10

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We have now seen how to solve trigonometric equations in right-angled triangles. We can use the same
techniques to help us solve trigonometric equations when the triangle is not shown.

Worked example 8: Solving trigonometric equations

QUESTION

Find the value ofifcos=0,2.

SOLUTION

Step 1: Use your calculator to solve for

To solve for, you will need to use the inverse cosine function on your calculator. This works backwards by

using the ratio of the sides to determine the angle which resulted in that ratio.

Press SHIFT cos 0. 2 ) = 78,4630478,46

Step 2: Write the final answer

78,46°

128 5.7. Solving trigonometric equations