Question

Which of the following trigonometric ratios are correct?

Answer 1

Hi there! In this problem, you should have the knowledge of three basic Trigonometric Ratio.

• sinA = opposite/hypotenuse
• cosA = adjacent/hypotenuse
• tanA = opposite/adjacent

Now that we know three basic ratio. Let's check each choices!

• sin50° = d/c

This choice is wrong because we focus on the 50° angle. When we focus on 50°, sin50° should be d/x and not d/c.

• sin50° = c/x

This choice is also wrong because in ratio, it's cos50° that adjacent/hypotenuse.

• tan50° = d/c

This choice is correct! As ratio states, tanA = opposite/adjacent.

• tan50° = x/c

This choice is wrong. x/c is a reciprocal of cosine which is 1/cos. We call the reciprocal of cosine as secant or sec in short.

• cos50° = x/d

This choice is wrong as x/d is a reciprocal of sine which is 1/sin. We call the reciprocal of sine as cosecant or cosec/csc in short.

• cos50° = c/x

This choice is right by the ratio. Nothing really much to explain since we follow by ratio that is defined.

Answer

• tan50° = d/c
• cos50° = c/x

Questions can be asked through comment.

Furthermore, tan also has its reciprocal form itself which is called cotangent also known as cot in short.

Hope this helps, and Happy Learning! :)