function

the starght line with equation y=3/4x makes an acute angle a with x-axis.     

(a) write down the vatue of tan a     
(b) find the value of sin 2a and cos 2a     

(a)  Since the line is "rise 3 run 4" the slope, and the tangent, is ³/₄ or 0.7500.     

(b)  We recognize a 3-4-5 triangle, and angle a is tan^–1 (0.7500) = 36.87^o     

       so we look up 73.74^o in the trig tables and find sin(2a) = 0.9600     

                                                                          and cos(2a) = 0.2800     

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