If #2sin(x) + 5cos(y) + 7sin(z) = 14#, then what is the value of #7tan(x/2) + 4cos(y) - 6cos(z)# among the following option?

Question

#A)4#
#B)-3#
#C)11#
#D)5#

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Answer 1 · 2018-01-11T06:25:36

11

Given that

#2sinx +5cosy+7sinz=14#

By inspection we see #x=pi/2,y=0and z=pi/2# satisfy the given equation.

Inserting these values in the expression we get

#7tan(x/2)+4cosy-6cosz#

#=7*tan(pi/4)+4*cos(0)-6*cos(pi/2)#

#=7*1+4*1-6*0=11#