$A+B=90^o\to B=90^o-A\\\\\cos B=\cos(90^o-A)=\cos90^o\cos A+\sin90^o\sin A\\\\=\cos A+1\cdot\dfrac{3}{5}=0+\dfrac{3}{5}=\dfrac{3}{5}\\\\\boxed{\cos B=\dfrac{3}{5}}$

$Used:\\\\\cos(x+y)=\cos x\cos y+\sin x\sin y\\\\\cos90^o=0,\ sin90^o=1$

Other method:

Look at the picture.

$\sin\theta=\dfrac{opposite}{hypotenuse}\\\\\sin A=\dfrac{3}{5}\to opposite=3\ and\ hypotenuse=5$

$\cos\theta=\dfrac{adjacent}{hypotenuse}\\\\adjacent=3\ and\ hypotenuse=5\to\cos B=\dfrac{3}{5}$

8 0

3 years ago

1)) An angle measures 132° less than the measure of its supplementary angle. What is the

Alexeev081 [22]

Answer:

156° and 24°

Step-by-step explanation:

Let it's supplementary angle be x.

So, the angle = (x - 132)°

As we know, sum of supplementary angles is 180°;

x + x - 132 = 180

2x = 180 + 132

2x = 312

x = 312/2

x = 156°

(x-132)° = (156-132)° = 24°

Hence, the angles are 156° and 24°.

5 0

2 years ago

Which relation defined by a mapping diagram is not a function?

Schach [20]

If one element in the domain mapped with more then one element in the range, the mapping is called one-to-many relation. One-to-many relations are not functions. Example: Draw a mapping diagram for the function f(x)=2x2+3 in the set of real numbers.

3 0

3 years ago